Without building it yourself there are far and few choices for a MH combo fixture to fit on a narrow tank like ours. I wish I had thought of it before hand or I would have gotten a wider tank setup. I paid a little more for my fixture but it's real nice and only 8" wide with no heat issues. It fits really well on my 55 and with the riser blocks I can slide it back to work in my tank. As you may know most fixtures are wider than the tank and believe me you don't want that.