Thank you for viewing. This is an original bolt/rod washer, brand new and unused, with 20 pieces included. The material is SUS304 stainless steel. While its strength is roughly equivalent to steel, it has excellent corrosion resistance, is highly rust-resistant, and has good mechanical properties. It is cast without burrs, with chamfered inner and outer edges. One side has a glossy finish, and the other has a hairline finish, allowing you to choose the loosening prevention effect depending on the installation direction. It also supports Sonar's minus-head bolts/rods and can be used on snares, toms, and bass drums. Compared to nylon washers, which are often used by various manufacturers in recent years, these washers have greater hardness and mass, resulting in a sharp, tight, and crisp sound with a sense of speed and directness. If you are dissatisfied with your drum sound, this is a more affordable way to achieve a noticeable change than replacing the hoops. Please note that we are unable to offer discounts due to rising prices and increased raw material costs. Thank you for your understanding.