This is a replacement Traxxas Large & Small Fiber Washer Set, and is intended for use with the Traxxas Bullet, Nitro Rustler and Nitro Stampede. These washers are made from a unique fiber material that wears as good or better than metal, making them an excellent option for clutch shims. The package includes six 5x8mm washers, and six 5x10mm washers.