Intermatic ELC4536 Standard Grade Electronic Photocontrol Locking-Type Mount Ideal for HID and LED fixtures totaling 550W at 277VAC Non-drifting silicon light sensor IR filtered for human eye response Power up on test delay of 45-60 seconds helps troubleshoot installation Exceeds 5000 on/off operations at full load UL certified to both US (UL773) and Canadian (TIL A15) safety standards