A bungee twine (occasionally spelled bungie), also known as a shock twine - and in Australia, an occy strap or octopus strap - is an elastic wire composed of one or extra elastic strands forming a center, usually included in a woven cotton or polypropylene sheath. The sheath does now not materially amplify elastically, however it's miles braided with its strands spiralling across the core so that a longitudinal pull reasons it to squeeze the center, transmitting the center's elastic compression to the longitudinal extension of the sheath and wire. Specialized bungees, such as some utilized in bungee jumping, can be made totally of elastic strands.
Bungee cords were used to provide a light-weight suspension for plane undercarriages from before World War I, and are nonetheless used on many small homebuilt plane wherein weight stays critical. Bungee cords had been also used in parachuting to assist in beginning the old-style parachute container after the ripcord become pulled.
Today, bungee cords are most usually used to secure gadgets with out tying knots and to take in surprise. Inexpensive bungee cords, with metallic or plastic hooks on every end, are marketed as a standard utility item. In Australia, this shape is referred to as an octopus, or "occy", strap. These can be an person strap, or a set of four hooked straps held collectively through a metallic ring allowing the occy strap to secure items around various tie points, as an instance a suitcase to a vehicle roof rack. Extensions of the idea are to be had as a coarse net of bungee cords with metal or plastic hooks around the periphery, for securing irregularly shaped loads of bags and cargo on the backs of pickup trucks, roofs of cars, and so on.
Bungee cords have additionally been used to make bungee chairs and for other purposes.