The lights are LED obviously.. its in a 4x4 area so I have 2 600w LEDs that replaced a 1000w for the same area. I have a number of LEDs - there are two different manufacturers in that tent - I believe one may be 10w epistar chips and the other 5w (ive had to replace a few over the years). LED is great - takes little power and produces a similar amount of lumens. It doesnt travel all the way to the bottom canopy as well HPS - but it also does not come with the heat issues/changing bulbs/fire hazard. I used them in one setup before commiting to them. I believe ripening takes about a week longer - other people think its faster. All I know is the end result is better looking than an HPS with less power being consumed - any further claims are speculative!