ROTAX engine part. Available as Certified and Non Certified part from the manufacturer.

O-rings give effective sealing over wide ranges of pressure, temperature, and movement, with the advantage of sealing pressure in both directions and reducing friction and wear on moving parts. MS28775 O-rings meet Spec. MIL-P- 5510A and are suitable for MIL-0-5606 hydraulic fluid at 160 degrees F. Available in different internal diameters and cross-sections (widths) in inches.

MS29513 series nitrile o-rings are resistant to fuel and are ideal for applications such as fuel injection connections and primers. They provide excellent resistance to petroleum-based products, hydraulic fluids, most silicone fluids and fuels. It is suitable for aircraft fuel uses (JP-4, JP-5). Not resistant to automotive fuels. Available in different internal diameters and cross-sections (widths) in inches.

A small amount of fuel proof grease applied to these O-rings helps the installation and operation of primers. 

M83248 series flurocarbon rubber (commonly known as Viton) o-rings are  made from an advanced rubber that has extremely good fuel and heat resistance and is ideally suited for aircraft fuel system applications. These o-rings feature a high temperature resistance, excellent resistance to acids, fuels, mineral and vegetable oils and greases, aliphatic, aromatic and chlorinated hydrocarbons, non-flammable hydraulic fluids (HFD) and many organic solvents and chemicals, low swelling in ASTM oil No. 1, and IRM 902 and IRM 903, excellent resistance to aging and ozone as well as low gas permeability and low compression set.

M83461 series rubber o-rings are flexible, preformed o-rings specially designed for aviation use and made from a high-quality rubber-like material that flexes and expands as conditions change, filling gaps and preventing dangerous leaks. They flex slightly to fill gaps and are often used at connection points where hoses or tubing connect to a port to prevent fluid leaks. They provide a better dynamic performance than MS28775 with excellent resistance to petroleum-based products, hydraulic fluids, most silicone fluids and fuels. They can be used with MIL-H-5606 Fluid, Aircraft Hydraulic Fluid. 

A grease seal, often called an oil or dirt seal, is a type of seal utilized to retain grease in a case or housing. Grease seals close spaces between stationary and moving components in mechanical equipment, helping prevent lubricant escape. Preventing harmful containments from entering machinery is another critical function of a grease seal. Oil and grease seals are available in numerous lip materials. Popular materials include felt, leather, urethane, nitrile, polyacrylate, ethylene-acrylic or polyacrylic, silicone, fluoro-elastomer, tetrafluoro-ethylene propylene and PTFE. Cleveland Grease Seals are intended for use in Cleveland Wheel Assemblies.