Direct-Lighting 50007 White Universal Line Voltage Track Lighting Head COMPATIBILITY : H system, 3-wire-1 circuit track system. 2-clip terminals on one side,1-clip terminal on the other side. 15/16-inch if measure from tip to tip. LAMP TYPE : Universal PAR. Accepts PAR20, R20, PAR30, BR30, BR40, PAR38 halogen or LED bulbs. BULB NOT INCLUDED. 120W max. SOCKET : E26 (aka Medium base or Screw-in base). FEATURE : 350 horizontal rotation or 90 vertical project. RATING : UL Listed. Trouble shoot video: http://youtu.be/QpwIEEQFJwg