This is a very energy-efficient bulb, perfect if you're trying to keep energy costs down. The socket on the bulb is the quite common E27 socket, also referred to as an intermediate socket.
Conrad Electronic
Philips Lighting 63820700 LED (monochrome) EEC D (A - G) E-27 28 W = 125 W Neutral white (Ø x L) 75 mm x 178 mm 1 pc(s)