HPI washer set used to hold the HPI super star wheels onto the following kits. RC10, JRX-2, T or Pro, Ultima, Nissan King Cab, Blackfoot, Monster Beetle, Lunch Box, Astute, and other Kyosho and Tamiya cars (and many more...) HPI washer set is silver in color Four of aluminum washers Flat on the back and tapered on the front INCLUDES: One Set of Four Super Star Aluminum Washers Required Parts Installing onto axle after wheel is in place, before nut is installed