BELL-SSAK.
The BEL-SSAK extraction system is used for the removal of exhaust from stationary vehicles (e.g., fire-brigade quarters) where absolute readiness for deployment is required. It is designed for vehicles with side or rear exhaust pipe. A uniquely shaped suction hood is connected to the vehicle exhaust by means of an electromagnet. On leaving the building, a limit switch deactivates the electromagnet and disconnects the exhaust hood, which is lifted away from the vehicle by an integral spring.
Please see data sheet below for exact duties.