O-ring, 28 x 5mm – Viton, Part# 4070488

This is a Viton O-ring. Its part number is 4070488 . An O-ring is a simple loop of elastic material. Its shape is a perfect circle. When you look at a cross-section, it looks like the letter “O”. That is where the name comes from.

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 . This O-ring measures 28 mm on the inside and has a thickness of 5 mm .

This O-ring is designed specifically for the Pfeiffer DUO 120A pump model . It is a fundamental and versatile component within Pfeiffer’s DUO family of vacuum pump models .

While the primary fit is for the DUO 120A, the same 28 x 5 mm Viton O-ring (under part number 02124025) is also compatible with:

• Pfeiffer DUO 125, DUO 255M (Index C)

• Pfeiffer DUO 10, DUO 10C, DUO 20, DUO 20C

• Pfeiffer UNO 30M

If you own any of these pumps, this O-ring may also fit your pump.