*Lid size is 18" x 18" and is made from strong 24 gauge 100% stainless steel
*Outside base size is ACTUALLY 12" X 12" and is made with 18 guage 100% stainless steel
*Set screws are 2" long and adjust to fit the different variations in flue sizes
*Fits any outside tile dimensions between 10" x 10" to 12" x 12"
*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