Aktore Power-Strut 158479 1/4" Clamping Nut with Long Spring are manufactured from mild steel cold rolled coil, and after stamping and machining operations are completed, they are case hardened, assuring positive biting action into the inturned edge of the Power-Strut Channel. Threads meet the Unified Screw Thread standard, ANSI B1.1, coarse series (UNC) class 2.