Dual Lamp Grow Light Fixture
February 3, 2019
There are also dual-watt and dual-lamp fixtures that allow you to use lamps of varying wattages and switch between MH and HPS lamps in the same fixture.
PC: Leslie F. Halleck
This is handy if you are transitioning young seedlings, cuttings, or plants in their vegetative phase to mature fruiting plants that consume more energy.