A coupling device consisting of two eyelets or other connection points connected in screw threads. The joint in between can be turned to shorten or lengthen the device with mechanical advantage provided by the screw threads
A device for connecting two parts of a bar, rod or rope together with an adjustable tension It consists of an internally threaded link turning on screws at each end threaded in opposite directions or- one end may have a swivel and the other a screw The link is operated by means of a wrench or a lever Frequently the link is constructed with a hole through the center for applying a marline spike as a lever