The Pro Light T5 HO Kit is ETL approved and is an extremely efficient low heat horticultural lighting system that uses T5 High Output (HO) lighting. T5 lamps provide the ideal spectrum for plant growth and are extremely efficient. Because of their minimal heat output, T5 lamps can be placed 6" to 8" above the plant canopy without scorching leaves, unlike metal halide lighting which must hang several feet above. Placing your grow lights closer maximizes photosynthetic response and leads to fuller growth at a lower wattage. The Pro Light T5 HO Kit includes T5 HO Grow Bulbs, built-in ballast, hanging hardware, a 12 FT grounded power cord and a two-year rebuild or replace warranty.