Powerflex Polyurethane Bush kit for Caterham 7 (DeDion With Watts Linkage) Large Upper Wishbone Rear Bush - PF8-904 - This bush is suitable for Road and Black Series applications. - Bush Size: 3/8 bore" - PRICE IS PER CAR KIT, NOT per bush. Powerflex usually price their bushes singly, but we have combined the QTY and price to keep it simple for you!