There are screw holes on two opposite sides, used to secure the grate in place. I removed 3 of these from a large Victorian structure in Cicinnati Ohio, they were all being used as wall vents. Just need to be cleaned, condition is very good. The item "Antique Large Floor Cold Air 24 x 24 Furnace Cast Iron Register Heat Grate" is in sale since Tuesday, February 07, 2017. This item is in the category "Antiques\Architectural & Garden\Hardware\Heating Grates & Vents".The seller is "itsfunbingme" and is located in Poland, Indiana. This item can be shipped to United States.