The Quasar Tubes Q-LED X CrossFade Linear Lamp 4ft is a Variable Color LED replacement for a T12 4' fluorescent lamps. These 50 watt tubes produce 90 lumens per watt! Quasar lamps are dimmable, flicker free and 25,000 hr average life. Best of all the Quasar Tubes are rugged, built with aluminum frame and plastic front diffuser. They can operate as a single tube or ganged together for a large light source. Featuring a CRI of 95+ and no green or magenta spike. The X Crossfade lamps have a wheel at the end of the unit to scroll to the desired setting color temperature from Tungsten 2000K to Daylight 6000K. 120 volt AC power is required at just one end of the tube, reducing cabling needs. Each lamp ships with (2) Q Boots and (1) Quasar Grounded Female Tri-Pin to Grounded Male Plug.