DETAIL ITEM AS FOLLOWING： 1，70W，100W，150W，175W，250W，400W（one ballast can fire one bulb) 2,70WX2,100WX2,150WX2,175WX2,250WX2(one ballast can fire two bulb) 3,70WX3,100WX3,150WX3,175WX3(one ballast can fire three bulb)