SpeedMaster small inline skeg strut and dual pickup rudder assembly. CNC Machine cut in the USA from High-Quality Aluminum. Straight blade rudder with dual water pickups and strut for 3/16" propeller shaft. We estimate this will work with 30"(750mm) to 40"(1000mm) catamaran hulls. Requires only 4 mounting holes for quick and easy mounting. -Skeg Style Strut -Rudder arm on both left and right side of the blade. Mounting plate measures: 29mm ("1.125") wide by 25.5mm("1.00) tall Weight: 125grams Includes everything in the picture, plus brass bushing. Requires: Cable with 3/16" propeller shaft.K&S 8131(1/4") Brass Stuffing Tubes