The Apollo? 4 is specifically designed for use with today?s high in-rush lighting ballasts. This is achieved by installing a ?ballast-rated? relay vs. the standard mechanical switch that is used in conventional 24 hr appliance timers. It features a precise 24 hr clock, quality enclosure and timer cover that resists dust and moisture. Assure the success of your plants by having the best lighting control in the market today. Dependability is critical in a lighting timer and failure is not an option! So use the right tool for the right job?the Apollo? 4. 10 Amps maximum/120 Volts/60 Hz./1000 Watts.