A TEE Moulding bit probably got its name from a TEE-BALL which is a stand used to support a stationary ball so that the player can strike it. The bit produces a special groove into a cornered moulding so that the inserted rubber “Bumper” will help it withstand the impact and cushion the panel, normally glass.

The three shown bits have a solid carbide cutting head with 2 flutes. Maybe used in a stationary or portable router machines, on a variety of woods including particle boards.