... electronic ballast 250w Electromagnetic ballasts for metal halide lamp,sodium lamp,mercury lamp 35W,70W,125W,150W,250W,400W,600W,1000W, ... For HS:(high-pressure sodium) discharge lamp; MH:(high-pressure metal halide) discharge lamp; HM:(high-pressure mercury vapour) ... temperature rise, noiseless, little magnetism leakage, long lifetime 3) The lamp can start quickly and have soft stable light 4. ...