Flexzion Mechanical Programmable Grounded Timer 24-hour 15A On/Off 2 Plug in Outlets Switch For Indoor Home Grow Tent Lighting Blower Aquarium Lamps Seasonal Portable Fans 24-hour mechanical plug-in timer with grounded 3-prong plug Ensure timer is disconnected from power supply Press down the segment pushbuttons according to how long you require the system to stay on Cycle 24 Hour, Each segment is 15 minutes Turn the timer dial until the black pointer is set to the present time