Like some others I was able to discover that the A4 Guide the wrong lamps for the brake / taillight lists (W21W). These have a different base and do not fit in the lamp socket. After several bad buys I have now found the right lamp: good quality impr
Bought very good for the brake lights of a VW Golf 6 Bj. 2009. Beware, shine as it should be and do their job. Will I buy it again the next time an illuminant fails.