2/3/5pcs Dia 20mm M10 *2/3/4/5/6/7/8/9/10 to 40mm Aluminum Alloy Gasket Flat Washer No Threaded Bushing Standoff Spacer Sleeve Size = Inner dia (d ) * Outer dia (D) * Height (L) Processing method: high-precision CNC lathe CNC milling mechanical device processing(Support for customization) Note that dimensions needs to be measured utilizing a vernier caliper If you need to order, please consult visitor service.