The washer is used when the hole is larger in diameter than the fastening nut. There are many different sizes of washers that you can use for different purposes. Purpose: The washer is a thin disk-shaped plate with a hole in the center, usually used to distribute the load of a threaded fastener such as a bolt, a nut, etc. Other uses are as a spacer, wear pad, preload indicator device, locking device, and to reduce vibration. High quality bolted connections require hardened steel washers to prevent loss of preload after torque is applied. Washers are also important to prevent corrosion galvanic, especially insulating steel bolts from aluminum surfaces. Usage: Widely used in flange and chemical connections Factory, power plant, Nuclear power plant and consumer electronics products, Hardware, precision instruments, electrical equipment, bearings, air pumps, Water pumps, water valves, cylinder pneumatics, sealing of high pressure brake systems etc. Specification: - Material: Copper