O-ring, 40 x 2.5mm – Viton, Part# 320480 – vacstellar

This is a Viton O-ring with precise dimensions of 40 mm inner diameter and 2.5 mm cross-section. Designed for Pfeiffer DUO and UNO series vacuum pumps, it provides a reliable, chemical-resistant seal for critical applications .

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 is used in the DUO 1.6, DUO 3, and UNO 6 pumps .

You will often find this O-ring included in major repair kits. For example, it is part of the Major Overhaul Kit for Pfeiffer DUO 1.6 and DUO 3 pumps . That means it is a standard part that gets replaced during a full pump rebuild.