Jaw opening
Clamping width provided by vise or clamp (see "Type")
In this case, the width of the clamp means the maximum distance that the jaws or stops of the tool can be spread, in other words, the maximum size of an object that can be clamped with this device.
Large clamping width, on the one hand, makes the tool more versatile and expands its capabilities; on the other hand, it affects the dimensions, weight and price, and also makes it difficult to work with small objects (a large tool is poorly suited for this). So, when choosing according to this parameter, you should not chase after the maximum margin, but take into account the size of the parts that you really plan to work with: for example, it hardly makes sense to buy a 500 mm clamp if you need a clamp for gluing plywood planks together.
Jaw width
Tool jaw width. It is indicated mainly for vices (see "Type") — among the clamps there are not so many models equipped with jaws.
Larger jaws provide a more secure hold, especially with large workpiece sizes, but make it difficult to work with small parts, and also affect the dimensions and weight of the entire tool.
Jaw height
Tool jaw height. It is indicated mainly for machine vices (see "Purpose of a vice") — among the clamps there are not so many models equipped with jaws, and for other types of vices this parameter is not so critical. In the case of a machine tool, the height of the jaws actually corresponds to the clamping depth (see above)