O-ring, 8 x 2 mm – Viton, Part# 4070949

This is the Pfeiffer O-ring, Part# 4070949. It looks small, but it plays a big role. It creates a tight seal inside your pump. Without a good seal, your pump cannot work right.

Exact Fit for Your Pfeiffer Pump
This O-ring is made to Pfeiffer’s exact factory size. It has an inside diameter of 8 mm. The thickness of the rubber is 2 mm .

Because it is a replacement part, it fits perfectly on these pump models:

• Pfeiffer DUO 5

• Pfeiffer DUO 5C 

  This is not a cheap rubber ring. It is made from Viton (also called FKM). This material is special because it can handle tough conditions.

  Here is why Viton is the best choice:

  • Handles High Heat: Your pump gets hot during long work hours. Viton stays flexible and does not melt or harden.

  • Resists Chemicals: It stands up to pump oils, fuels, and other harsh fluids. It will not swell, crack, or break down.

  • Lasts Longer: Viton is much more durable than standard rubber. You will not need to replace it as often.

  • Better Seal: It stops air and gas from leaking through. This helps your pump reach a strong vacuum.