Stepped drill bit, stop collar, and thickness gauge/wrench for Kreg? Pocket-Hole JigsWorks with materials from ?" to 1?" thickDrill bit features easy-set etched markings for ?", ?", 1?" materialsStop collar window aligns with etched markings on drill bit for easy setupThickness Gauge measures material thickness, has built-in hex wrenchDirect replacement for items included with Kreg? Pocket-Hole Jig 320, 310Also works with K5, K4, K3, R3, Mini, and Foreman