250W Timing Dimmable HPS Electronic Ballast (dimmi

250W HPS Timing Dimmbale Electronic Ballast (diming ballast) Type:TT-NG250DTxx, The first x means the time span,in other words, how many hours later it will dim;the second x means the dimming range. E.g. TT-NG250DT56The power will automatically drop 40 percent after5 hours full power working Apply to whereit does not need so strong lighting in the deep night. Use this ballast no need to change the current road lighting system.By this means,it can save much moreenergy.