Tongue and groove router bits are specialized cutting tools used in woodworking to create interlocking joints known as tongue and groove joints. These joints are commonly used in constructing panels, flooring, cabinet doors, and other applications where a strong, seamless connection between two pieces of wood is desired. Tongue and groove router bits consist of two separate bits, a tongue bit and a groove bit. The tongue bit is used to cut a projecting tongue along the edge of one piece of wood, while the groove bit cuts a corresponding groove or channel along the edge of the mating piece. When assembled, the tongue fits snugly into the groove, creating a tight joint.