will accommodate up to a 2" (5.1 cm) mast. A 1-1/2" OD (3.8 cm) or larger heavy wall tubing mast should be used. If using pipe (not the same as structural tubing), 1-1/4" pipe = 1.66" OD and 1-1/2" = 1.91 OD. Also keep in mind that most smaller rotators can't