You can get forged adjustable clamps from Vachhani Impex that can immediately change heights without blocks or shims. The most popular clamps used in woodworking are C clamps, sometimes known as G clamps. Most clamps have a sliding cross pin handle or wing nut that is used to tighten the clamp as part of its structure.
Some of the heavy-duty forged clamps that we produce include screws that end in square heads. With these clamps, a wrench is used to tighten them. The screw has a swivel pad at the end that makes it possible to set the clamp on non-parallel jobs and avoid marring the work.