A closed body rigging screw, also known as a turnbuckle, is a mechanical device used to adjust the tension or length of a cable, wire, rope, or rod in applications such as rigging, construction, maritime, and various other industries. It consists of two threaded eye bolts, each with a right-hand or left-hand thread, which are connected by a central body. The body can be turned, effectively changing the distance between the two eye bolts and thus adjusting the tension in the connected material.