Dowel screws are threaded with wood screw thread on both ends, or machine screw thread on one end and wood screw on the other. Hanger bolts are headless bolts designed to hang materials from wooden structures, walls, or overhead. They feature a wood screw thread and pointed tip on one end with machine screw thread and blunt tip on the other. Variants included in this assortment feature coarse screw thread and run 5/8" to 2" in length. Full assortments of #4312 contain six (6) refills comprised of Hillman item numbers #4313 - #4318.