I know what the hell is this,,,,well after working on German cars now for over 31 years now,,,,we have finally redesigned the axle boot ,,,,this is a new G12 750 the new body style,,,while I was working on this car I noticed they changed the rear axle boot design. Over the years it has changed by how many ribs it had,,,,,or the rubber has now changed big time,,,,now it’s like some special plastic rubber,,,they should last for ever with the new material,,,,we see the new material in the X5 front axles boots,,,,the first X53 E53 would crack and spray grease everywhere,,,,,now the newer X5 E70,,,,don’t crack like the old one due to the new rubber plastic design.