Amazon.com: U-Bolt Pipe Clamp U Bolt Assembly For Outdoor Antenna,secure an antenna mast (as well as pipes and ropes) of up to 1 5/8” diameter 2pcs : Electronics
ILSCO Permaground Copper U-Bolt Ground Clamp, Conductor Range 2/0-4 Sol, Pipe Size 3/8 in. GPL-5-EC - The Home Depot
Stainless Steel Saddle U-Bolt Muffler/Exhaust Clamp, 2.25 Inch - Walmart.com
Adamax 2-in U-bolt Strut Beam Clamp in the Strut Accessories department at Lowes.com
Hardware Essentials 1/4 in. x 1-3/4 in. x 1 in. Stainless Steel U-Bolt with Plate and Hex Nuts (5-Pack) 320872 - The Home Depot