Each set contains 4 universal stainless steel washers for bushings or wheels. The washers are highly recommended for anyone using non-backless bearing wheels such as FlatFace G6 Bearing Wheels and others. The purpose of them is to put them between the truck and the wheel in order to increase durability. As you may have noticed, the area on some trucks where they come in contact with the wheel can be rough, increasing wear on your wheels. These washers provide a smooth surface for the wheels to roll against, increasing the lifespan of your wheels. The newest batches of Flatface G6 Wheels have been optimized for use with washers, and many other wheels are also compatible with washers. Please note that if your wheels do not spin because the nut is too tight when the washers are on, you may have a defective TechDeck truck where the axle is abnormally short, or you may have an older generation wheel not optimized for bearings. Another solution is to try a new nut, because some nuts will go on farther than others. These washers can also be used with bushings.