Irwin Tools 1900983 Marples 3-Wing Slot Cutter Router Bit with 1/4" 3-wing carbide tipped slot cutter router bit woodworking tool cuts smooth 1/4 inch slots Perfect router bits for grooving T-moldings, spline joints, tongue and groove joints, and many other applications Designed for use with IRWIN Marples slot cutter arbors Creates perfect flat-bottomed cuts Extended life, flawless finish