They go all the way.
Well, I know what the site says, but there are many reviews saying this clamp will not work on the max 4 inches. So, I would still like to know if the clamp can be used on something smaller than 3 inch diameter in size. Some of these clamps have slots that go around the entire circumference of the strap, other only go half way. So do the slots on this strap stop or go all the way around the strap?
Yes, this is an all stainless steel clamp
Anyone use it on a boat, will it rust?
Yes, the description says 3 to 4 inch. Your 3.5" requirement lands right in the middle.