*Gelco's signature cross braced lid size is 17" x 21" and is made from strong 24 gauge 100% 304 steel
*Double channel outside base size is ACTUALLY 13" X 17" and is made with 18 guage 100% 304 steel
*Set screws are 2" long and adjust to fit the different variations in flue sizes
*Fits any outside tile dimensions between 11" x 15" to 13" x 17"
*Base is designed to fit square, round, rectangular or oval flue tiles
*Screen is 8" high and has a 3/4" mesh screen
*Made in the USA and carries a lifetime warranty