... 2. CE & UL Dimmable Digital BallastKey Word: Electronic Ballast, Dimmable Electronic Ballast, Grow Light Ballast 400W, Hydroponic grow ballast 400w, electronic ballast 400w, 110V, UL Listed1) ... factor: <1.5 7) Max. Lamp distance from ballast: 15m/49ft 8) Ambient temperature: -25 ~ +50 ... protection function 3) Dimming, adjustable output power 4) Light weight, small size, non-flickering, noiseless 5) ...