These truss spacers' posts are drilled for 10/24 bolts and have a polyurethane coating. They are 4 inches high and 12-3/4 inches wide. They are used to lower a contoured canoe seat's center of gravity, and are only sold as a pair. The optional hardware comprises four 6-inch stainless steel 10/24 bolts with a finish washer, flat washer, and lock nut.