Windlock a revolutionary product, reduces the risk of container stacks to be blown over in high winds. Windlock is a patented manual twistlock with a hook for connecting two adjacent containers in a stack and reduces the risk of a stack being blown over in high winds. The twistlock locks into the top front two corners castings of an empty container before it is placed in the top row of a stack. When the container is lowered into position the hook element drops into the corner castings of the adjacent container. A technical report of the TNO University shows that a horizontal connection of a row of containers provides a very high level of protection against high winds.