Grower's Choice digital lighting controller allows the cultivator to control up to 200 fixtures. It works with all GC-315 CMH, GC- 630NS CMH, GC-1000 DE fixtures, & ROI Series LED grow lights. This dual-channel controller permits daisy chaining as many as 100 fixtures per zone. Allowing complete control of your growing area with timed on/off switching, sunrise/sunset, and also accurate temperature readings with dual thermal probes and thermal-threshold automatic dim-shutdown for added protection.