This is a pack of ten ProTek R/C 2.6x6x0.5mm Shock Piston Washers. These washers have a 2.6mm inner diameter, with a 6mm outer diameter and are 0.5mm thick. These can be used in a variety of applications, but are intended to be used as shock piston washers. They can also be installed between an aluminum clutch shoe and the flywheel, and used as clutch shoe shims on any clutch that uses a 2.6mm pin.