This cap offers .625in mesh and the ability to fit square round rectangular or oval flue tiles. The 18-ga. Screen is 8in high. The base is 18-ga. And the lid is 24-ga. It is made of 100 percent 304-alloy stainless steel. Measures 13in x 13in. Fits 11in x 11in to 13.5in x 13.5in.