Shunted Lampholders – will have 2 holes (or accept 2 wires) on the unit.
Unshunted Lampholders – will have 4 holes (or accept a total of 4 wires) on the unit.
Shunted Lampholders are to be used with Instant Start Ballasts, and Unshunted Lampholders are to be used with Rapid Start Ballasts. An unshunted lampholder may be converted to a shunted lampholder by taking a short wire and stripping both ends. Next take one end of the wire and insert it into one hole on the left side of the lampholder, taking the other end and stick it into one of the holes on the right side of the unit. Thus, making a jump from one side to the other, and now it becomes a shunted lampholder.
Please go to www.semperlite.com and search for your shunted or unshunted lampholder.