Replacement lamp only, (fixture sold separately) Hydrofarm's induction lights are similar to fluorescent lights in that they use gasses, which, once '"excited," react inside the tubes to produce white light. Unlike fluorescent lamps, induction systems are rated at 100,000 hours. This is because fluorescent lamps must use electrodes to "excite" the gases inside the tube, whereas induction lamps use the principle of induction - the transmission of energy by way of magnetic field. Features: Long lumen maintenance - 90% output at 70,000 hours Energy efficient - consumes 50% of conventional lighting systems Long life - 100,000 hours High lumens / watt output Maintenance costs - go 10-20 years without a change out Lower heat output - reducing cooling costs High color rendering index - 85 CRI Color temperature 3,100K- perfect for plant growth Low starting ignition temperatures -40º F - good for colder applications Instant re-strike - no warm up needed "Instant-on" capability - can be used with photocell or motion sensor No flickering or glare Quiet operation Environmentally safe UL recognized