Product Details: 30mm x 8 pieces The above, 3 sets Total: 24 pieces Size: φ30, Inner diameter 16mm, Outer diameter 25mm, Thickness 0.5mm These are silicon flat washers for noise reduction in arcade sticks (Arcade Controller). They are used by attaching them to the buttons of the arcade stick. By attaching these, noise reduction and shortening of the button stroke are possible. Since they are 0.5mm thick, you can adjust the stroke to some extent by stacking multiple pieces. Please note that interference may occur with some buttons, requiring modification of the parts. Although they are new and unused, they may have minor scratches. They will be shipped stacked in groups of 3 pieces, as shown in the second photo. Additional washers are available for both sizes, 3 pieces for 100 yen. Please comment with the size and the number of sets you would like to add.