WIT-Trolley System. The system is operated by the Sartocheck® 4 Filter integrity tester on top of the trolley. The Trolley System includes the equipment needed for automatic water intrusion testing (WIT), e.g., pressure tank for the test water, pneumatically controlled valves, PLC. It is easy to move the system right to where the filters to be tested are located. Only the tubing for filling as well as the external pressure transducer need to be connected to the filter housing. Flexibility: Besides automatic WIT, the system can also be used for standard integrity testing of hydrophilic filters by the diffusion and bubble point test. Additionally the pressure tank can be in-line steamed (max 2 bar g) together with the stainless steel reinforced filling tube and valve set.