Apollo Horticulture APL400 Hydroponic 400 - Watt HPS MH Digital Dimmable Electronic Ballast for Grow Lights 400 Watt Ballast Adjustable at 100%, 75% and 50% for maximum efficiency, Up to 30% more lumens than magnetic ballasts for improved yields, Compatible w/ both MH and HPS bulbs Compatible w/ 120V and 240V power supplies (We include a 2 meter 120V cord), High frequency output results in less power loss (50/60Hz Frequency), 99% Power factor Short circuit protection by automatic power shut off for ultimate safety, Fast lamp ignition by lighting up the bulbs within 1-2mins max, Stable light output by constant lamp voltage, lamps will be flicker free Built in cooling fan and Graduating fin design to minimize ballast temperature, Light weight (Under 10lbs), CE certified and ETL listed. Each Unit Includes a 3 year Warranty. Package Includes: 1  400 Watt Ballast / 1  120 Volt Power Cord / 1  Pamphlet