Replacement ballast UVP-06212 for White-Rodgers UV100 single lamp ultra-violet system. Assembly includes ballast transformer with wiring harness and a 4-pin fixture for the single lamp. The ballast has the 120v connection on the black and white wires and a green wire for chassis ground.Base side of the ballast measures 5 x 3". Base is 1-3/8" thick. Wire length for fixtures is 12 inches.