Guitar Nut Cube. this single Nut Cube can be used to tighten or loosen nuts or bushing for machine heads, toggle switches, potentiometers, and so on. Cube can be inserted under volume or tone knobs easily. 5 in 1 design : 2 x metric hex nut (10mm and 11mm), 1 x inch hex nut (1/2") ,16mm knurled nut and 1 x multi (knurled nut of U.S. made toggle switches etc.) Stainless steel, made in Japan. Size: 30mm x 30mm x 30mm HOSCO original design.