1 1/4 x 3 1/2" A325 TC BOLT

Transform your steel frame construction with A325 TC bolts, also known as tension control bolts. The head has a unique round shape and is not meant to be driven, but the shank contains a spline that is easily secured with a specialized power shear wrench to prevent turning while tightening the nut. As you reach the desired tension, watch as the spline breaks off, leaving you with a sturdy and perfectly secured structure.

https://lrkdindustries.com/products/1-1-4-x-3-1-2-a325-tc-bolt