Closely together stacked and stored containers must be secured to prevent them from moving, slipping, or tipping over. This is especially important when the containers are unloaded. The required level of security in the storage and transport of steel boxes as well as the best possible protection of the cargo is guaranteed with horizontal and vertical securing elements.

Bridge fittings are ideal for securing containers horizontally. These variable connecting elements are hooked into the upper touching corners of adjacent containers. By turning the threaded rod of the bridge fitting with an open-end wrench, the steel boxes to be connected are pulled together tightly. The connected containers are stable next to each other and do not slip. However, pairs of containers connected by bridge fittings cannot be lifted as one unit. The bridge fittings only serve as horizontal protection against slipping and are not suitable for securing stacked containers.

Stacking cones are used for the temporary vertical securing of stacked containers. These massive elements are hung in the lower four corners of the container to be stacked. The steel box equipped in this fashion can then be placed on another container. The conical lower ends of the assembled stacking cones grip into the cast steel corners of the container below and prevent slipping. Since containers to be stacked have to be lifted anyway, stacking cones can be mounted at a comfortable working height of the container to be stacked. It is not necessary to inspect the roof of the container below.

Twist locks offer a permanent way of securing stacked containers. These are inserted into the upper four corners of the container below and locked using a lever. After the container to be stacked has been set down, the two containers are firmly connected by actuating the lever a second time.