16mm 19mm 22mm Black Metal Push Button Switch Waterproof Illuminated Led Light Flat Momentary Latching with Power Mark 12V 220V Very important: Connectors are purchased individually 1 What does the signal "NC" and "NO" means? "A" "+": effective pole of the led "LED" " - ": adverse pole of the led " NC ": Normal Close " NO ": Normal Open " C " : Common 2 How to connect? 1 Connect " NO " and " C " : The circuit is alway open until press the button 2 Connect " NC " and " C " : The circuit is alway close except press the button 3 Will I get a seal ring for every button? Yes,each button will have a free seal ring Product Specifications: Product Name: Push Button Switch Switch Combination: 1NO1NC Opening Diameter:16mm/19mm/22mm Max Current: 3A Operation Type: Self-recovery 、Self-lock LED Colors: Red Yellow Blue White Green LED Voltage: 3-6V;9-24V;110-220V Waterproof Level: IP65 Customization: Yes , please depart a message to us What does the signal "NC" and "NO" means? " NC ": Normal Close " NO ": Normal Open " C " : Common 16mm 19mm 22mm Black Metal Push Button Switch Waterproof Illuminated Led Light Flat Momentary Latching with Power Mark 12V 220V