Wikipedia
StanFlex (also known as STANFLEX or Standard Flex) is a modular mission payload system used by the Kongelige Danske Marine ( Royal Danish Navy, KDM).
Originally conceived during the 1980s as a way of replacing several classes of minor war vessel with a single class of multi-role ships (the Flyvefisken class), the StanFlex system consists of weapons and equipment mounted in standardised containers, which can be loaded into slots on the ships. These containers can be swapped out in a short period of time, allowing the ship to switch between roles when needed.
The success of the modular payload system led the KDM to design all new warships with StanFlex slots, and to install slots on older vessels during major refits. By 2012, nine ship classes capable of carrying StanFlex payloads will be in service.