1Made of 45 steel, black oxide finish, features high hardness, high strength, durable in use 2Undersized to fit machine table slot case hardened 3It is used for T-slot aluminum extrusions to connect other parts 4Bottom of T-Slot nut is staked to prevent the stud from protrusion 5T-Slot nuts enable the user to add clamps to a fixture without tearing down existing clamps