These are the Horticultural Lighting Group (HLG) LEDs and these are the flagship models. Now Horticultural Lighting Group and their quantum board design has revolutionized the LED industry. They've made LEDs that are extremely thin, simple yet powerful. These are literally like a no-frills LED. So, let me tell you a little story that not many people know about HLG. The thing is HLG was actually born out of two separate LED companies. One of them being Johnson Grow Lights by a guy named Stephen Johnson and the other one called Northern Grow Lights by a guy named Amit Chandra. Now, these guys were Stephen, being a grower, very experienced while Amit, being an engineer, they both had a real big fascination with LEDs and both their companies were focusing on COB LED lights. Chip-on-board for those of you not familiar.