Originally Posted by AdamLein
Where'd you get these clamps?
They are stocked at Fisheries Supply. They are also standard items on a lot of rail-mount hardware (Dickinson uses them for their BBQs, my Jim-Buoy life ring also uses them).
They are distributed by Sea-Dog:
Sea-Dog : Quality Marine, Industrial and Rigging Hardware
The plastic is pretty soft, so they don't have the highest clamping power. They really only work for this if used in a balanced way. They are inexpensive though.