For outboard engines up to 150hp. Unbalanced: the number of turns lock-to-lock is not equal port to starboard and vice-versa. UC68-OBS side mount cylinder features a patented turning nut for a fast and easy installation to the engine tube. Clearance required at the engine tube side is 340mm (13.3"). Recommended for use where maximum boat speed do not exceed 40mph (40knots).