IVY Classic 45511 5/16"-18 Hanger Bolt Driver, Impact Plus, 10-Pack Allows drills or impact drivers to drive hanger bolts and threaded rods Internal threads and ball shaped stop at base of hanger bolt driver allow for easy thread release Alloy-Steel for extra strength and durability Built to withstand the high torque (rotational force) of impact drivers, Impact Plus (Registered Trademark) Thread Size: 5/16" - 18, Length: 1-5/8", Shank: 1/4" hex power