APEM Seal Caps for Toggle/Pushbutton Switches – Full and Half – APEM U1600, The APEM Seal Cap U1600 Half with Hex Nut Nickel Coated, Black is an excellent solution for preventing dust, sand and water from getting into switches, while in cold weather, it also prevents ice from blocking lever action. Suitable for bushing APEM Series 12000, 3500 and 6000 switches. APEM U1600 Seal Cap Half with Hex Nut Nickel-coated Black