USHIO G36T5L 39W Germicidal Low Pressure Mercury-Arc Lamp HID Bulbs produce high output for their size making them a compact powerful &amp; efficient light source HID Bulbs are used for general lighting, professional lighting fixtures, growing applications HID bulbs put out around 3-5 times greater output (lumens per watt) than traditional halogen bulbs Ushio bulb, 39W, Base: Fa8 Single Pin, Rated Life (hours): 9000, Color Temp: , Luminous Flux (LM):