I can't answer this technically because I don't know but I know the bar style LEDs (fluence, pro grow) you hang alot closer than the quantum board style, but you will get alot less penetration with the bar style. They are made more for limited height applications and racking systems. More the commercial growers I think. HLG are bringing out a bar style light soon but only because the market demands it, they will tell you themselves that quantum boards work better. I've always been a HID fan and the HLG650R is the first LED grow light I've owned, and I can't fault it so far. Buds are chunky and frosty underneath it, good penetration and good spread. For the price though it will be a long time before I convert all my lights and you would bloody expect them to work for almost 2 grand a piece.