Quick Clamps (Trigger Clamps)

A quick clamp (or trigger clamp) ratchets its jaw along a bar one squeeze at a time with a pistol-grip trigger, and releases instantly with a separate lever -- genuinely one-handed operation, which no screw-driven clamp can match. That speed comes at a real cost in maximum clamping force: a quick clamp is very good for holding parts in position, light glue-ups, and anywhere a clamp needs to go on and come off fast, but generally can't match an F-clamp or parallel clamp for a glue-up that actually needs serious pressure.

Cheap ones flex and creep under real load; a decent-quality quick clamp is worth paying for if it's going to do more than hold a jig steady for a moment.