The old wipers were a bit of a faff to get off because you have to push in the locking catch and slightly twist the wiper down to get the locking catch to release the blade. Once that'ts done it's simple as you just push the new blades on the wiper arms until it clicks and it's marvellous to have a streak free screen again. Audi says that you have to use their parts but I had an original rear wiper on a sportback that was agony when it was in use as it sqeaked abysmally then after fitting a Bosch replacement it was blissful silence so stick to Bosch folks for great windscreen wiping in silence.