Used for making strong plate joints, or biscuit joints, that join separate pieces of wood together.
The tool is plunged into the workpiece to cut a slot that accepts various size biscuits. Most models come with different blades to create various slot sizes. The slots of one piece of wood are then aligned with the slots of the other peice being joined. These slots share the same biscuit.
Has top-mounted or side-mounted sliding switches and comes with a dust bag or an adapter for hook-up to a shop vacuum.
Good joiners will have adjustable fences for making a joint at a variety of angles.