Top Gun Mounting Plate Highest quality aircraft aluminum protected by the toughest anodizing. Extruded design offers maximum support when mounting outriggers into an aluminum T-Top or similar structure. Machined openings are available in horizontal or 10-degree offset..Designed to weld into any top, supplied at 20" in length, they can be cut to fit your application. Rupp mounting plates have a 2.50" center hole with 5/16-18 threaded mounting holes at 3" x 5" centers.