Welcome to SZ Number, the leading manufacturer of horticultural ballasts in the world. The reason for this is simple that the ballast manufactured by SZ Number is the most advanced HID horticultural ballast on the market. Our ballast is the leader in innovation and has more patents applied for and issued than any other ballast s on the market. SZ Number is continually advancing our ballast design to be more efficient. This is done through technological breakthroughs that SZ Number is the leader and everyone else tries to follow. We have the largest distribution network in the industry with the best after sale service. Our ballasts are available in both Fan and non-Fan model. When trying to choose your next ballast, look to the industry leader, SZ Number.