M83248 series o-rings are flurocarbon rubber o-rings. Flurocarbon rubber is commonly known as Viton. It is an advanced rubber that has extremely good fuel and heat resistance and is ideally suited for aircraft fuel system applications.
Only McFarlane has FAA approval to replace the old, less fuel resistant nitrile (MS series) and synthetic rubber (NAS series) o-rings with the latest fuel proof fluorocarbon o-rings. To find our FAA-PMA replacement o-rings go to O-Rings and Gaskets and look for the MCM83248 series o-rings.
McFarlane also has complete fuel selector, fuel shut-off valve, and fuel strainer seal kits with all required seals and gaskets. Go to Fuel Selector/Shut-Off Valve Seal Kits or Fuel Strainer Parts to find the kit for your aircraft.