*Lid size is 21" x 21" and is made from strong 24 gauge galvanized steel
*Outside base size is ACTUALLY 16" X 16" and is made with 18 guage galvanized steel
*Set screws are 2" long and adjust to fit the different variations in flue sizes
*Fits any outside tile dimensions between 14" x 14" to 16" x 16"
*Base is designed to fit square, round, rectangular or oval flue tiles
*Screen is 7" high and has a 3/4" mesh screen
*Made in the USA and carries a 7 year workmanship warranty