A limited number of KB pistons have the ring grooves crossing the piston pin hole. In order to have the piston rings properly supported these pistons come with piston ring support rings. As support rings do not have a sealing function they do not have to be replaced when you install new piston rings, but sometimes new ones are needed because a ring is lost or broken.
Recommended Retail Prices excluding sales tax.
Prices exclude shipping, import duties and installation.