For 2000 2001 2002 2003 2004 Audi A4 and Audi A6 with 3.0L V6 5V AVK or BBK series of engines. For All years Audi A6 with Z15L TDI engines. Special 3/8″ Drive Socket designed specifically to adjust the variable timing on the exhaust camshaft to base position when performing timing belt or other front-engine service on Audi 3.0L, 5 valve engines.