This little mount helps lifting up LEDs for better lighting in the tank. The mount was designed for Aquariums with 5mm glas. In my case i use it on a Dennerle Scapers Tank with Trocal LEDs. The LED i use is a little bit too long for my tank, the mount fixes this by adding around 1.5 - 2cm of width on each side. If your LED has a mounting system similiar to the one on the pictures you can also switch between two heights.