Delta 17-924 Mortising Attachment with 4 Chisel and Bit sets. Includes: 1/4 in. x 1/4 in., 5/16 in. x 5/16 in., 3/8 in. x 3/8 in. and 1/2 in. x 1/2 in. hollow chisels and drill bits, special alignment gauge for fast, accurate set ups, large, cast iron fence assembly, bushings, guides, hex wrench and instructions.