This kit includes Kreg's Easy-Set Pocket-Hole Drill Bit, the same 3/8'' stepped bit included with the Kreg® 310 and 320 Pocket-Hole Jigs (#65391 and #61493, sold separately). It also includes the same Easy-Set Stop Collar and Material Thickness Gauge/Hex Wrench included with those jigs. The bit has engraved markings for 1/2'', 3/4'', and 1-1/2'' thick materials to match up with the window on the Easy-Set Stop Collar. Its 1/4'' hex shank fits standard quick-change chucks. The Material Thickness Gauge allows you to easily determine material thickness, and has markings for 1/2'', 3/4'', and 1-1/2'' thicknesses. A built-in hex wrench works to tighten the stop collar. Collar also fits all other standard (3/8'' diameter) Kreg pocket-hole drill bits. Compatible with all Kreg Pocket-Hole Jigs, including K5, K4, K3, R3, Mini, and Foreman jigs.