... HPS&MH CE,TUV,UL,CUL approved No fans inside ul certified electronic ballast, electronic grow ballast. Welthink series grow light digital, electronic ... hobby gardening industries,etc. The features of the Welthink series Grow light ballast,digital ballast.Run for HPS and ... and maintenance free operation.Soft startingDimming function is option.Approval: UL,CUL, EMC, ROSH,CE,TUV.Suitable Bulbs400W, 600W, ...