I was thinking the same thing... Be careful with that diffuser, I broke the one on my NOS 2X F8T5 preheat undercabinet light just from taking it out. I had superglued it only to have it break again so I just threw it out. Oh well, it works fine without a diffuser... When I had bought my F15T8 preheat undercabinet light from the ReStore, I made sure to grab the diffuser off another one as well, so I'd have a replacement diffuser but it seems to the F15T8 has a much less brittle diffuser than the squared Lithonia diffuser, which tends to break right at that corner. Pretty stupid of them to design a diffuser with a squared off corner when the lens has to be bent to be removed. A round front would better spread out the tension of bending the diffuser so it doesn't snap.