The table (Fig. 2) summarizes the relationship between clamp size, recommended vessel diameter and clamp pressure. "Vessel diameter" refers to the external diameter of the vessel in its natural state of full dilation.

There is a 50% overlap in the recommended vessel diameter range, between each clamp size and the next larger or smaller size. Thus, for every vessel diameter, with the exception of those at the extreme ends of the range, there will always be two suitable clamps. Whenever a choice arises, the smaller clamp should be selected to ensure a gentler, less pressured handling of the vessel