The clamp unit (for hand tightening) is an auxiliary tool for holding and securing the workpiece while working. If the work is not firmly secured, it will lift up or become misaligned, so a clamp unit that is optimal for each work will be required. The shape and size vary depending on what is secured and how to secure it, such as a slide clamp that secures the workpiece from the side, etc. In addition, there are various types of clamp units, such as a type suitable for thin clamps that tighten while pressing the claw at the tip downward, a type that can be tightened steplessly according to the height of the workpiece, a side jack ideal for large processing machines, etc. Therefore, it is necessary to select the best one according to the application, work environment, etc.