Rigging couplers have the hole through one end, you use a nut on them and then tighten them into a clevis, when tight just tighten up the nut onto the clevis so it doesn't come loose. Turn Buckles are fantastic to use on the wire rigging of Bipes. Both work great but the rigging coupler is a lighter system . The come in both 2-56 and 4-40.