Designed for router table use, this set can be used to create slots, grooves and rebates from 3.2mm to 18mm in depth. The set includes: 4 x three winged cutters 3.2, 4, 4.8, and 6.4mm in width. 1/2" shank arbor. 17 shims (8 x 0.1mm, 4 x 0.5mm, 3 x 1mm and 2 x 4mm).N.B. The carbide edges of the cutters should never touch; arrange the cutters to prevent this. Use only the thicknesses provided in the set. Be sure all cutters are assembled in the correct rotational direction.Safety tips: Never use the slot cutter set without shims between the cutters. The distance between the cutters can vary from 1mm to 1.7mm. A shim must also be positioned between the ball bearing and the cutters.