A trigger clamp can be used with only one hand so is sometimes called a one-handed bar clamp,  it is versatile and can be used in many areas including home, workshop and garden as well as being very reliable. They have a quick release button or lever allowing free movement of the moveable jaw, the trigger can then be used with each press further tightening the jaws to hold the workpiece firmly, with further squeezes the clamping pressure can be increased. Afterwards the quick release can be used to open the jaws. Some trigger clamps have a ratchet mechanism to better secure the workpiece. Trigger clamps are available with reversible jaws and can also be used as spreaders. Trigger clamps are useful for both wood and metal working and are available in both light-duty and heavy-duty.