Tensor lights are a direct light source used by many numismatists to examine and grade coins. Tensor lights provide full spectrum lighting simulating natural daylight and providing true to life colors. Our 13 watt Tensor lights include an adjustable shade that when closed automatically shuts off the light. Operates off of standard 110 electrical outlet. Replacement bulbs are also available. Older models used two prong bulbs while newer models used 4 prong bulbs. Check your bulb to see how many prongs it has before ordering replacement bulbs. If you are ordering extra bulbs at the same time as buying a light, order the 4-prong bulbs as our current stock of lights used 4-prong bulbs.