LED bi-pin lamps are an energy efficient, long-lasting and effective replacement for current halogen bi-pin lamps. A bi-pin is a standard from the International Electrotechnical Commission (IEC) for lamp fittings. Bi-pins are used on many LED lights including LED MR11 & MR16.

The letters G, GU, GX, GY, GZ etc determine the diameter of the pin and its shape. The numbers following the letters describe the distance between the pins. For example, a G4 would have a distance of 4mm from the center of one pin to the center of the other pin.