The Isotta Vacuum System is an underwater housing vacuum system is a device or set of devices used to verify the watertight integrity of an underwater camera housing before diving. It helps prevent camera housing floods by creating negative pressure (vacuum) inside the housing and monitoring the vacuum pressure to ensure there are no leaks or air bubbles present. Comes with a hand pump. 
Handmade in Italy.
The vacuum system is compatible with any brand of underwater housing with an open M16 threaded port.