Master Mechanic, Quick Change, Countersink Set, Drill, Countersink Or Counterbore In Wood & Plastic, 1/4" Hex Shank For Quick Change Adapters, Includes 4 Power Groove Countersinks: #6-3/32", #8-7/64", #10-1/8" #12-1/8" & Allen Wrench For Depth Adjustment, Carded.