The Panacea Adjustable Aluminum Deck Mount Bracket easily mounts to a 2-inch by 4-inch or 2-inch by 6-inch deck rail. Space the braces according to the size of your flower box, allowing for 3-inch of overhang on each side, to accommodate a large range of box sizes. Measures 12-inch length by 0.75-inch width by 3.375-inch height.