1/4"-20 x 1/2" Hot Dip Galvanized Steel Coarse Thread Carriage Bolts 100PK The square section grips into the part being fixed (typically wood), preventing the bolt from turning when the nut is tightened..
072" x 4" 18-8 Stainless Steel Extension Springs 3PK Their turns are normally touching in the unloaded position, and they have a hook, loop or some other means of attachment at each end..