Turnbuckle

A turnbuckle is a device for adjusting the tension or length of ropes, cables, tie rods, and other tensioning systems. It typically consists of two threaded eye bolts, one screwed into each end of a small metal frame, with one bolt cut with a conventional right hand thread and the other with a left hand thread, so that turning the central frame screws both eye bolts in or out at the same time, adjusting the tension without twisting the eye bolts or whatever is attached to them. Turnbuckles are used wherever meaningful tension needs adjusting, from light duty garden fences to heavy duty structural components in buildings and suspension bridges. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/