... vertical adjustment. 3.size:5", 8",10",12" Galvanized Steel trailer roller Keel Mount BracketOne piece roller bracket with slot for ... vertical adjustment. Mounts with 1/2" bolt and is designed to ... 8", 10", 12"2.Package: carton, metal cage3.Hot dipped galvanized finish4.Factory manufacturer. Galvanized Steel trailer roller Bracket