O-ring, 25 x 3.0 mm – Viton, Part# 320180

This is a Viton O-ring. Its part number is 320180 . An O-ring is a simple loop of elastic material. Its shape is a perfect circle. 

You place this O-ring into a groove between two metal parts. When you tighten the parts together, the O-ring gets squished. It fills the tiny gap completely. This creates an airtight, leak-proof seal . Under pressure, the elastomer material behaves like an incompressible fluid, which actually reinforces the sealing function . This O-ring measures 25 mm on the inside and has a thickness of 3.0 mm .

This O-ring is made specifically for these Pfeiffer DUO pump models :

• Pfeiffer DUO 5

• Pfeiffer DUO 5C

• Pfeiffer DUO 10

• Pfeiffer DUO 10C

If you own any of these pumps, this is the right O-ring for you. It is also included as a standard component in the Major Overhaul Kit for the DUO 5 (Part # PKE32008T) , which contains one of these O-rings .