Pretty tight inside there. Note there is only one starter. One ballast is standard preheat and the other has an internal electronic starter (though both are magnetic; the one with the internal starter starts like a programmed start ballast). I currently have no use for this light, but I've been wanting a fixture for my F13T5 lamps for awhile now and couldn't resist making a Frankenfixture out of this crappy Lithonia strip light. The good thing about these modern cheap fixtures is that all you need to chop one down to a shorter length is a pair of tin snips and pliers to straighten the channel after you chop it!