Rareelectrical.com » 1999, Audi, A4

Products for:

  • (X) Year: 1999
  • (X) Make: Audi
  • (X) Model: A4

View Universal items for: 1999, Audi, A4

Browse Products

Sort
View
 
Items 1-33 of 33
Rareelectrical - 120 Amp Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8T 1781Cc Dohc 20V 1998-2005 Vw
120 Amp Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8T 1781Cc Dohc 20V 1998-2005 Vw
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212A4
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 120 Amp Alternator Compatible With 1998-2005 Vw Passat 1.8L Turbo 2.8L V6 Gls Glx 1997-1999 Audi A4
120 Amp Alternator Compatible With 1998-2005 Vw Passat 1.8L Turbo 2.8L V6 Gls Glx 1997-1999 Audi A4
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212B3
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 120A 12V Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8T 1781Cc 1998-2005 Vw Passat
120A 12V Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8T 1781Cc 1998-2005 Vw Passat
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212A1
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 120A 12V Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8T 1998-2005 Vw Passat 1.8L 2.8L
120A 12V Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8T 1998-2005 Vw Passat 1.8L 2.8L
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 120A 12V Alternator Compatible With 1998-2005 Vw Passat Gls Gl Glx 1.8L 2.8L V6 1997-1999 Audi A4
120A 12V Alternator Compatible With 1998-2005 Vw Passat Gls Gl Glx 1.8L 2.8L V6 1997-1999 Audi A4
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212B4
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 120A 12V Type Pma Alternator Compatible With 1992-2000 Audi A4 Quattro A6 100 90 Cabriolet Vw Passat
120A 12V Type Pma Alternator Compatible With 1992-2000 Audi A4 Quattro A6 100 90 Cabriolet Vw Passat
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • VW/Audi: 078-903-015F / 078903015F / 078-903-015FX / 078903015FX • VW/Audi: 078-903-015A / 078903015A / 078-903-015C / 078903015C • VW/Audi: 078-903-017A / 078903017A...More Details »
Item #: 13357
Condition: New
Price: $164.99
Sale: $94.28
Save: 43%
Save: $70.71
Qty:

Rareelectrical - 120A Alternator 12V Compatible With 1997-1999 Audi A4 1.8T 1998-2005 Vw Passat Gls Gl 1.8L Turbo
120A Alternator 12V Compatible With 1997-1999 Audi A4 1.8T 1998-2005 Vw Passat Gls Gl 1.8L Turbo
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212A5
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 12V 120 Amp Alternator Compatible With 1998-2005 Volkswagen Passat Gls Gl Glx 1.8L 2.8L 1997-1999
12V 120 Amp Alternator Compatible With 1998-2005 Volkswagen Passat Gls Gl Glx 1.8L 2.8L 1997-1999
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212A2
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 12V 120A Alternator Compatible With 1998-2005 Volkswagen Passat 1.8T Gls Gl 4Motion 1997-1999 Audi
12V 120A Alternator Compatible With 1998-2005 Volkswagen Passat 1.8T Gls Gl 4Motion 1997-1999 Audi
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212B2
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - 12V 90A Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8L Aeb Turbo & 1998 Vw Passat 1.8L
12V 90A Alternator Compatible With 1997-1999 Audi A4 A4 Quattro 1.8L Aeb Turbo & 1998 Vw Passat 1.8L
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • (OE): A13VI138 / A13VI156 • Tech: 2541856 / 2541895 / 2565363 • 439069 / 436640 / NA503 / VA401 • VW/Audi: 058-903-016-A / 058903016A • VW/Audi: 058-903-016-B /...More Details »
Item #: 13814
Condition: New
Price: $165.76
Sale: $94.72
Save: 43%
Save: $71.04
Qty:

Rareelectrical - Alternator 120A 12V Compatible With 1998-2005 Vw Passat Gls Gl 1.8L Turbo Glx 2.8L V6 1997-1999 Audi
Alternator 120A 12V Compatible With 1998-2005 Vw Passat Gls Gl 1.8L Turbo Glx 2.8L V6 1997-1999 Audi
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212B1
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - Alternator 120A Ir/If Fits 1997-1999 Audi A4 Quattro 1.8T Aeb 1998-2005 Vw Passat 1.8L Turbo 2.8L V6
Alternator 120A Ir/If Fits 1997-1999 Audi A4 Quattro 1.8T Aeb 1998-2005 Vw Passat 1.8L Turbo 2.8L V6
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212A3
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - Alternator 12V 120 Amp Compatible With 1998-2005 Volkswagen Passat 1.8T 2.8L V6 Gls Gl 1997-1999
Alternator 12V 120 Amp Compatible With 1998-2005 Volkswagen Passat 1.8T 2.8L V6 Gls Gl 1997-1999
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Audi / VW: 06B-903-016-AD / 06B903016AD • Audi / VW: 06B-903-016-E / 06B903016E • Audi / VW: 06B-903-018-EX / 06B903018EX • Reman: AL9404X • Service:...More Details »
Item #: 11212B5
Condition: New
Price: $284.64
Sale: $162.65
Save: 43%
Save: $121.99
Qty:

Rareelectrical - Clutch Flywheel Conversion Kit Compatible With 1997-2005 Audi Volkswagen A4 Passat Quattro 1.8L OEM
Clutch Flywheel Conversion Kit Compatible With 1997-2005 Audi Volkswagen A4 Passat Quattro 1.8L OEM
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • VOLKSWAGEN: 58141999 • VALEO: 52285615 • DISC SIZE: 9" / 15/16" / 23" • DUAL MASS FLYWHEEL OPTION: 52285606 SPECIFICATIONS: • Type: Clutch Flywheel...More Details »
Item #: 52285615*3
Condition: New
Price: $332.96
Sale: $190.26
Save: 43%
Save: $142.70
Qty:

Rareelectrical - Clutch Flywheel Conversion Kit Compatible With 1997-2005 Audi Volkswagen A4 Quattro A4 Passat 1.8L
Clutch Flywheel Conversion Kit Compatible With 1997-2005 Audi Volkswagen A4 Quattro A4 Passat 1.8L
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • VOLKSWAGEN: 58141999 • VALEO: 52285615 • DISC SIZE: 9" / 15/16" / 23" • DUAL MASS FLYWHEEL OPTION: 52285606 SPECIFICATIONS: • Type: Clutch Flywheel...More Details »
Item #: 52285615*1
Condition: New
Price: $332.96
Sale: $190.26
Save: 43%
Save: $142.70
Qty:

Rareelectrical - Clutch Flywheel Conversion Kit Compatible With 1997-2005 Audi Volkswagen Passat Quattro 1.8L OEM
Clutch Flywheel Conversion Kit Compatible With 1997-2005 Audi Volkswagen Passat Quattro 1.8L OEM
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • VOLKSWAGEN: 58141999 • VALEO: 52285615 • DISC SIZE: 9" / 15/16" / 23" • DUAL MASS FLYWHEEL OPTION: 52285606 SPECIFICATIONS: • Type: Clutch Flywheel...More Details »
Item #: 52285615*2
Condition: New
Price: $332.96
Sale: $190.26
Save: 43%
Save: $142.70
Qty:

Rareelectrical - Front Wiper Motor Compatible With 2001-2002 Audi S4 All Trims/All Engines 1998-1999 Volkswagen All
Front Wiper Motor Compatible With 2001-2002 Audi S4 All Trims/All Engines 1998-1999 Volkswagen All
(0) Reviews: Write first review
Description: Front Wiper Motor - 1996-2002 Audi A4 / 2001-2002 Audi S4 Brand new front wiper motor. Direct OEM replacement for part number 8D1955113A. OEM PART NUMBERS: • AUDI, VOLKSWAGEN:...More Details »
Item #: WPM3503*2
Condition: New
Price: $240.22
Sale: $137.27
Save: 43%
Save: $102.95
Qty:

Rareelectrical - New 12 Volt 120 Amp Alternator Cw Ir/If Compatible With 1997-1999 Audi A4 Quattro 1.8L 1781Cc L4
New 12 Volt 120 Amp Alternator Cw Ir/If Compatible With 1997-1999 Audi A4 Quattro 1.8L 1781Cc L4
(0) Reviews: Write first review
Description: VOLKSWAGEN / AUDI OEM PART NUMBERS: • VW/Audi: 06B-903-016B / 06B903016B • VW/Audi: 06B-903-016E / 06B903016E • VW/Audi: 06B-903-016AD / 06B903016AD • VW/Audi: 06B-903-018EX /...More Details »
Item #: 11214*1
Condition: New
Price: $484.16
Sale: $276.66
Save: 43%
Save: $207.50
Qty:

Rareelectrical - New 12 Volt 70 Amp Alternator Fits Audi A4 Quattro 1.8L 2000 2001 0-986-044-340
New 12 Volt 70 Amp Alternator Fits Audi A4 Quattro 1.8L 2000 2001 0-986-044-340
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016 BOSCH: 0-124-315-010 BOSCH SERVICE EUROPE: 0 986 044 340 0986044340 HELLA: 8EL012426631 8EL-012-426-631 8EL-737-782-001 VALEO REMANUFACTURED: 437177 ITEM DESCRIPTION:...More Details »
Item #: 13921N-70AA4
Condition: New
Price: $345.07
Sale: $197.18
Save: 43%
Save: $147.89
Qty:

Rareelectrical - New 120A 12V Alternator 5-Groove Clutch Pulley Cw Compatible With 2000-2005 Volkswagen Passat Gl Gls
New 120A 12V Alternator 5-Groove Clutch Pulley Cw Compatible With 2000-2005 Volkswagen Passat Gl Gls
(0) Reviews: Write first review
Description: VOLKSWAGEN / AUDI OEM PART NUMBERS: • VW/Audi: 06B-903-016B / 06B903016B • VW/Audi: 06B-903-016E / 06B903016E • VW/Audi: 06B-903-016AD / 06B903016AD • VW/Audi: 06B-903-018EX /...More Details »
Item #: 11214*2
Condition: New
Price: $484.16
Sale: $276.66
Save: 43%
Save: $207.50
Qty:

Rareelectrical - New 12V 120 Amp Alternator Internal Regulator Compatible With 1997-2005 Audi A4 B5 A6 C5 1.8L Turbo
New 12V 120 Amp Alternator Internal Regulator Compatible With 1997-2005 Audi A4 B5 A6 C5 1.8L Turbo
(0) Reviews: Write first review
Description: VOLKSWAGEN / AUDI OEM PART NUMBERS: • VW/Audi: 06B-903-016B / 06B903016B • VW/Audi: 06B-903-016E / 06B903016E • VW/Audi: 06B-903-016AD / 06B903016AD • VW/Audi: 06B-903-018EX /...More Details »
Item #: 11214*3
Condition: New
Price: $484.16
Sale: $276.66
Save: 43%
Save: $207.50
Qty:

Rareelectrical - New 12V 70A Alternator Fits Audi A4 1.8L 1999-01 06B-903-016 0124315010 Al0709x
New 12V 70A Alternator Fits Audi A4 1.8L 1999-01 06B-903-016 0124315010 Al0709x
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016 BOSCH: 0-124-315-010 BOSCH SERVICE EUROPE: 0 986 044 340 0986044340 HELLA: 8EL012426631 8EL-012-426-631 8EL-737-782-001 VALEO REMANUFACTURED: 437177 ITEM DESCRIPTION:...More Details »
Item #: 13921N-70AA1
Condition: New
Price: $345.07
Sale: $197.18
Save: 43%
Save: $147.89
Qty:

Rareelectrical - New 12V 70A Alternator Fits Audi Europe A6 Avant 1997-05 8El737782001 0124315010
New 12V 70A Alternator Fits Audi Europe A6 Avant 1997-05 8El737782001 0124315010
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016 BOSCH: 0-124-315-010 BOSCH SERVICE EUROPE: 0 986 044 340 0986044340 HELLA: 8EL012426631 8EL-012-426-631 8EL-737-782-001 VALEO REMANUFACTURED: 437177 ITEM DESCRIPTION:...More Details »
Item #: 13921N-70AA3
Condition: New
Price: $345.07
Sale: $197.18
Save: 43%
Save: $147.89
Qty:

Rareelectrical - New 12V 70Amp Alternator Fits Skoda Europe Superb 2001-06 2007 2008 8El737782001
New 12V 70Amp Alternator Fits Skoda Europe Superb 2001-06 2007 2008 8El737782001
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016 BOSCH: 0-124-315-010 BOSCH SERVICE EUROPE: 0 986 044 340 0986044340 HELLA: 8EL012426631 8EL-012-426-631 8EL-737-782-001 VALEO REMANUFACTURED: 437177 ITEM DESCRIPTION:...More Details »
Item #: 13921N-70AA5
Condition: New
Price: $345.07
Sale: $197.18
Save: 43%
Save: $147.89
Qty:

Rareelectrical - New 12V 90 Amp Alternator Fits Audi A4 1.8L 1999-2001 0124325017 8El-012-428-171
New 12V 90 Amp Alternator Fits Audi A4 1.8L 1999-2001 0124325017 8El-012-428-171
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016A 038-903-018EX 038903018EX BOSCH: 0 124 325 017 0124325017 0-124-325-036 BOSCH REMANUFACTURED: AL0725X BOSCH SERVICE EUROPE: 0 986 044 300 HELLA: 8EL 737 783-001...More Details »
Item #: 13921N-90AA4
Condition: New
Price: $343.61
Sale: $196.35
Save: 43%
Save: $147.26
Qty:

Rareelectrical - New 12V 90A Alternator Fits Audi A4 Quattro 1.8L 2000 2001 0-124-325-036 Al0725x
New 12V 90A Alternator Fits Audi A4 Quattro 1.8L 2000 2001 0-124-325-036 Al0725x
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016A 038-903-018EX 038903018EX BOSCH: 0 124 325 017 0124325017 0-124-325-036 BOSCH REMANUFACTURED: AL0725X BOSCH SERVICE EUROPE: 0 986 044 300 HELLA: 8EL 737 783-001...More Details »
Item #: 13921N-90AA1
Condition: New
Price: $347.25
Sale: $198.43
Save: 43%
Save: $148.82
Qty:

Rareelectrical - New 12V 90A Alternator Fits Skoda Europe Superb 2001-06 2007 2008 038-903-018Ex
New 12V 90A Alternator Fits Skoda Europe Superb 2001-06 2007 2008 038-903-018Ex
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016A 038-903-018EX 038903018EX BOSCH: 0 124 325 017 0124325017 0-124-325-036 BOSCH REMANUFACTURED: AL0725X BOSCH SERVICE EUROPE: 0 986 044 300 HELLA: 8EL 737 783-001...More Details »
Item #: 13921N-90AA3
Condition: New
Price: $343.61
Sale: $196.35
Save: 43%
Save: $147.26
Qty:

Rareelectrical - New 12V 90Amp Alternator Fits Audi Europe A6 Avant 1997-05 Al0725x 8El737783001
New 12V 90Amp Alternator Fits Audi Europe A6 Avant 1997-05 Al0725x 8El737783001
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016A 038-903-018EX 038903018EX BOSCH: 0 124 325 017 0124325017 0-124-325-036 BOSCH REMANUFACTURED: AL0725X BOSCH SERVICE EUROPE: 0 986 044 300 HELLA: 8EL 737 783-001...More Details »
Item #: 13921N-90AA5
Condition: New
Price: $343.61
Sale: $196.35
Save: 43%
Save: $147.26
Qty:

Rareelectrical - New 70Amp Alternator Fits Audi Europe A4 Avant 1998-2001 0-986-044-340 Al0709x
New 70Amp Alternator Fits Audi Europe A4 Avant 1998-2001 0-986-044-340 Al0709x
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016 BOSCH: 0-124-315-010 BOSCH SERVICE EUROPE: 0 986 044 340 0986044340 HELLA: 8EL012426631 8EL-012-426-631 8EL-737-782-001 VALEO REMANUFACTURED: 437177 ITEM DESCRIPTION:...More Details »
Item #: 13921N-70AA2
Condition: New
Price: $345.07
Sale: $197.18
Save: 43%
Save: $147.89
Qty:

Rareelectrical - New 90Amp Alternator Fits Audi Europe A4 Avant 1998-2001 038903018Ex 06B903016a
New 90Amp Alternator Fits Audi Europe A4 Avant 1998-2001 038903018Ex 06B903016a
(0) Reviews: Write first review
Description: AUDI, VOLKSWAGEN: 06B903016A 038-903-018EX 038903018EX BOSCH: 0 124 325 017 0124325017 0-124-325-036 BOSCH REMANUFACTURED: AL0725X BOSCH SERVICE EUROPE: 0 986 044 300 HELLA: 8EL 737 783-001...More Details »
Item #: 13921N-90AA2
Condition: New
Price: $347.25
Sale: $198.43
Save: 43%
Save: $148.82
Qty:

Rareelectrical - New Front Wiper Motor Compatible With 1996-2002 Audi A4 All Trims/All Engines Quattro All Trims/All
New Front Wiper Motor Compatible With 1996-2002 Audi A4 All Trims/All Engines Quattro All Trims/All
(0) Reviews: Write first review
Description: Front Wiper Motor - 1996-2002 Audi A4 / 2001-2002 Audi S4 Brand new front wiper motor. Direct OEM replacement for part number 8D1955113A. OEM PART NUMBERS: • AUDI, VOLKSWAGEN:...More Details »
Item #: WPM3503*1
Condition: New
Price: $240.22
Sale: $137.27
Save: 43%
Save: $102.95
Qty:

Rareelectrical - New Front Wiper Motor Compatible With 1998-1999 Volkswagen All Trims/All Engines Passat 8D1955113a
New Front Wiper Motor Compatible With 1998-1999 Volkswagen All Trims/All Engines Passat 8D1955113a
(0) Reviews: Write first review
Description: Front Wiper Motor - 1996-2002 Audi A4 / 2001-2002 Audi S4 Brand new front wiper motor. Direct OEM replacement for part number 8D1955113A. OEM PART NUMBERS: • AUDI, VOLKSWAGEN:...More Details »
Item #: WPM3503*3
Condition: New
Price: $240.22
Sale: $137.27
Save: 43%
Save: $102.95
Qty:

Rareelectrical - New Starter Motor 12V 1.1Kw Pmgr Cw 9-Tooth Compatible With Bosch 1997-2005 Audi A4 Quattro Vw
New Starter Motor 12V 1.1Kw Pmgr Cw 9-Tooth Compatible With Bosch 1997-2005 Audi A4 Quattro Vw
(0) Reviews: Write first review
Description: OEM PART NUMBERS: • Bosch: 0-001-107-012 / 0001107012 • Bosch: 0-001-107-013 / 0001107013 • Bosch: 0-001-107-017 / 0001107017 • Bosch: 0-001-107-018 / 0001107018 • Bosch:...More Details »
Item #: 17751
Condition: New
Price: $218.40
Sale: $124.80
Save: 43%
Save: $93.60
Qty:

Items 1-33 of 33

View Universal items for: 1999, Audi, A4