The Rubber Cupped Foot screws directly onto the shaft end of the JounceShock.The high durometer Cupped Foot is normally used in conjuction with the Domed Target(which is bolted or welded to the control arm or axle).This Foot targets your JounceShock to meet the Domed Target area with up to 30 degrees of motionThe Rubber Cupped Foot is both quiet upon impact and durable making it ideal in reducing noise for those who use their JounceShock equipped vehicle as an everyday driver. California Residents WARNING