It's a 10 gallon, with a heating matt sized for a 10 gallon... i think it acctually takes up about 1/3 of the back pannel. and I'm using analog gague.. I'm looking at getting a digital one depending on how much I have at the end of this pay check. In the time I posted this to now I resprayed the ground, and completely covered the screen with tin foil. With only a small section cut out for the heat lamp.