Hydrofarm convertible ballasts feature engineered transformers made to the exacting American National Standards Institute specifications. They are designed to drive either halide or sodium bulbs properly with separate wire leads. They are marked accordingly to UL standards for use with either bulb. We pair this engineered unit with our heavy duty multi-pole switch for the ultimate in safety - the convertibles you can count on. *Use Halide for growing and Sodium flowering - all in the same system.