It has to be nylon or plastic as it doesn't seal at all. Maybe I'm bad. but they claim that they are all tested before shipping. Or is it just a statement of the type of rubber seal. Yes, you get what you pay for.
π¨ Robinair (15115) VacuMaster Single Stage Vacuum Pump - For Efficient Single-Stage Vacuuming, Delivers 1.5 CFM
9 Review
Enhanced Elitech ILD-300 Infrared Refrigerant Leak Detector: Advanced HVAC Halogen Tester with Selectable Gas Functionality
9 Review
π UView 560000 Combustion Leak Tester: A Reliable Tool for Efficient Diagnosis
9 Review
Lichamp Automotive R1234YF Installer Standard
9 Review