Bosch Gen 4 sprocket carrier o-ring external. Part No PLB40533
£1.37 incl VAT£1.14 excl VAT
This O-Ring sits between the front chainring (or chainring spider) and the lock nut. The O-ring is not fitted to all bikes, a new one should only be fitted if an old one is removed.
Bosch Generation 4 motor BDU4xx.