Cat® Spacers are commonly used to provide additional stretch length in a fastener to lower preload loss or to lower the cyclic stress range of machine operating loads. They are used to establish and maintain the functional relationship of dependent parts in machine systems. Cat® Spacers are thick rings made of plastic fixed under a nut or the head of a bolt to spread the pressure when tightened or to provide a standoff between two surfaces.Application:Cat® Fasteners to help you build it, maintain it, or fix it - for most machine and workshop applications throughout the world. Consult your owner's manual or contact your local Cat® Dealer for more information.