Tight wall conditions for 1½-inch handrail tubing. The 511/1H is the flange your installer reaches for when two mounts share a corner joint. Or when a column return won't clear a 3-inch round base. Or when a booth divider sits closer to the wall than a standard flange allows. The trimmed sides preserve full base contact at the tubing collar, so the flange seats as cleanly as the standard 510/1H. A set screw in the collar locks the tubing in place. Construction adhesive is an option for permanent installation. Solid brass develops a natural patina over time and polishes back to original shine. 304 stainless wipes down daily in retail and hospitality interiors without pitting.