If you really need to hold big items this Quick Fist clamp will do the job. The two seperate straps will hold items of up to 38 cm (15″) in diameter or 71cm in a linear distance.
Price is for two clamps.
• Two 35.6cm (14’’) separate straps hold round objects up to 38,1cm (15”) in diameter.
• Holds equipment measuring up to 71.1cm (28”) in linear distance.
• Each clamp supports a safe working load of 68kg (150lbs) with a break-strength of 176kg (300lbs).
• Two clamps support 136kg (300lbs) with a break-strength of 272 kilos (600lbs).
• Each half of the clamp mounts with four #10 screws or bolts.
• Mounting Area: 51mm x 51mm (2” x 2”)
• UV resistant.