Clamp collars for pole mounts.
1.05" OD -- For 3/4" PVC - For standard 3/4" schedule 40 PVC
1-1/8" OD -- For poles such as Summit pole and Humminbird MEGA 360
1-1/4" OD -- For Wooster Sherlock SR054 Extension Paint Pole or Wooster GT
1-1/3" OD -- For 1" PVC -- For standard 1" schedule 40 PVC
Even 1/8" makes a big difference. P