In the field of connectors, a very broad range is covered, in diverse areas such as aeronautics, weapons systems, nuclear, medical, automotive — and many more besides.
What makes these particular connectors different is often the material they are made from, or the treatment associated with their use (frequently involving plating); sometimes they are magnetic – or specifically non-magnetic.
In certain cases, the temperature tolerated is very low with respect to the penetration required, as the components they enclose are very sensitive.