O-ring, 35x 5 mm – Viton, Part# 320525 – vacstellar

This O-ring is made from Viton. Viton is a special rubber that handles heat very well. It also resists oils and chemicals much better than standard rubber . This makes it perfect for the tough conditions inside a vacuum pump .

This particular O-ring fits several popular Pfeiffer pump models. It works with the DUO 250A and DUO 120A pumps . It also fits the UNO 250A pump .

the PMK024 Overhaul Kit for the DUO 120A pump, where two of these O-rings are used . It is also part of the PSK027 Seal Kit for the DUO 250A pump, also with a quantity of two . That means it is a standard part that gets replaced during a full pump rebuild.

If you are already opening up your pump for service, replacing this O-ring is a smart move. A worn or incorrect O-ring can cause leaks. That can hurt your pump’s performance. This part fits perfectly and seals tightly .