Container castings are the corners of the container. Corner castings are structural components of containers, allowing them to be connected horizontally or vertically to other containers, as well as to modes of transport including ships, railways and highways. When containers are connected together, corner castings provide the necessary structural connection points required for many different types of container connectors, such as container double-end twisted locks, container weldable twisted locks, and container bridge clips. Dual-end container torsion lock allows two corner pieces to be connected vertically together, which come in two basic types, manual and semi-automatic torsion lock. Manual torsion lock is the most widely used unit, with a fracture load of 500 kn, suitable for all applications, they are mainly used for cargo ship applications. Semi-automatic torsion locks are mainly used in the railway industry, where double stacking containers on railway trucks produce higher loads. They are self-locked, but must be released manually.