BonyTek 7-Day LCD Digital Programmable Timer Switch, Energy-Saving Plug-in Timer Socket Outlet for Indoor Home Grow Tent Lighting Blower Aquarium Lamps ? 8 Function Keys, 12/24 Hours Changeable: Time setting is including hour, minute and week. Large LCD display, easy to read and set. Perfect for fish tank & garden. ? Easy To Install & Program: 24-Hour / 7-Day programming setting. This timer switch allows you to control the electronic power to the appliance, and saving energy cost. ? Various Combination Settings: Allows same setting Mon-Fri or 7 days; Same set with Mon-Fri + Sat + Sun; Individual setting. This time switch allows you to set programs for individual days or various combinations of days.The timer can be used to set up to 10 "on/off" group timers per day. ? Plug-in Design: Rechargeable battery backup assures you stay on schedule even after a power outage. Not suitable for fluorescent, low energy or discharge lamps. ? Random Function: Random switching function and summer mode, featuring DST daylight saving time & RND/random vacation setting. Features a random setting to have your lights to go on and off at random times during your absence.