Sizes: #1) 1/8″-1/4″, #2) 1/4″- 5/16″, #3) 5/16″-7/16″ #4) 7/16″-9/16″ #5) 9/16″-3/4″. High Carbon Alloy Tempered Steel, Multi-Fluted Extract a wide variety of screws, easy to use Hardened for long life, Reverse Thread, locks on and backs out broken studs