The pin-lock AC-54 control damper is designed with a .080 extruded aluminum hat shaped frame and a single thickness blade that has an intergral section in the blade to accept the ½" spline shaft.

The extruded aluminum spline shaft turns effortless in the double sealed bearings (Celcon inner and polycarbonate outer). The AC-54 is equipped with both blade and jamb seals of extruded silicone material.