The Hillman Group 160293 1 1 1 6-32 Square Nut, 100-Pack

A Square Nut is a four-sided nut that can be used in a channel or welded into place. Square nuts have a greater surface in contact with the part being fastened and therefore provide greater resistance to loosening, but also a greater resistance to tightening as well. Square nuts are used along with flat washers in order to avoid damage from their sharp edges and help to increase the strength of the fastener.