Kreg® Pocket-Hole Jig K4. Alternatively, the K4 can be screwed into a workbench or other surface. Kreg Pocket-Hole Screws. Kreg Pocket-Hole Plugs. (1) Pocket-Hole Jig K4. The three-hole drill guide lets you make perfectly placed pocket holes in a wide variety of material widths and thicknesses — from 12mm to 38mm.