Growers Choice Master ControllerGrowers Choice digital lighting controller enables the grower to control up to 200 fixtures. It is compatible with all GC 315 CMH, GC 630NS CMH, GC 1000 DE fixtures, & ROI Series LED grow lights. This dual channel controller allows daisy chaining up to 100 fixtures per zone. Enabling complete control of your growing environment with timed on off switching, sunrise sunset, and precise temperature readings with dual thermal probes and thermal threshold