Hex Lag Screws are used to fasten wood and/or metal pieces to each other and can also be used to affix items to concrete or masonry when combined with lag expansion shields. Lag screws feature a heavy-duty construction and usually have a hex head type to facilitate installation with a simple hand wrench. Variants included in this assortment measure 5/16" in diameter and range from 1" to 4" in length. Full assortments of #40230 contain seven (7) refills comprised of Hillman item numbers #40231 - #40237.