im getting the 300 for my teratec1200,15.2 internal dia so should be a nice snug fit.just gotta wait for tank now,being made by nd,custom 243l,handemade 3d background(hide all tubes behind) arcadia eco-aqua led lighting,gonna look mint when ive got it all set up and scaped))I have the 300 and the 200 - they're great. make sure it is the right size for your hoses.