Hello everyone.. this may seem and is probably a stupid question, but I'm in the market for buying my Sulcata hatchling a new light. I want something that'll not only emit UVB rays but some heat too, and I was just wondering... I measured my current fixture and the whole thing is 24", but just the bulb alone is 23". My question is, all the lights I've seen come in sizes 24", is this correct? Or do I have to go by the measurement of the bulb alone?

Thanks!