O-ring, 42 x 2.5 – Viton, Part# 320485

This O-ring is quite popular. It fits many different Pfeiffer DUO pump models. Here is the full list:

• Pfeiffer DUO 1.6

• Pfeiffer DUO 3

• Pfeiffer DUO 6

• Pfeiffer DUO 6M

• Pfeiffer DUO 11

• Pfeiffer DUO 11M

• Pfeiffer DUO 11MC 

  This O-ring is not sold just by itself. It comes as part of several repair kits for Pfeiffer pumps. You will see it in:

  • Major Overhaul Kits for DUO 1.6 and DUO 3 

  • Minor Repair Kits for DUO 1.6 and DUO 3 

  • Seal Kits for DUO 11 pumps 

  • Maintenance Kits for DUO 6 and DUO 11 

  • Overhaul Kits for DUO 11MC 

  If you are buying a repair kit for your DUO pump, this O-ring is likely inside. But if you lose it or damage it, now you know the part number to get a replacement.this one is made from Viton (FKM). This material is tough. It handles heat well and resists chemicals. It also stops gas from leaking through, which is very important for vacuum pumps .