Router Rabbeting Bit 1 1/4" x 3/8" 3/8" Depth 1/4" Shank KP3501 - Protech
For cutting rebates
Rabbet: (răb′ĭt) also re·bate (rē′bāt′,răb′ĭt)
A cut or groove along or near the edge of a piece of wood that allows another piece to fit into it to form a joint.
By choosing alternative bearings with a larger outside diameter, the depth of cut can be reduced. The cutting height can be increased with multiple passes.
Popular with picture framers and joinery where a lap joint is required.