Turnbuckles are normally used for rigging or tensioning of wires, ropes, rods etc. They are designed for straight / in-line rigging, tensioning or lashing. It normally consists of two threaded eye bolts, one screwed into each end of a small metal frame, one with a left-hand thread and the other with a right-hand thread. The tension can be adjusted by rotating the frame, which causes both eye bolts to be screwed in or out simultaneously, without twisting the eye bolts or attached cables.
They combine strength and durability, yet are simple to set up and adjust from supporting a fence in a garden to extremely large turnbuckles used as support to high-rise buildings or bridges