RS PRO FKM O-Ring, 21mm Bore, 23mm Outer Diameter

Introducing the range of RS PRO FKM O-Rings, ideal for use as seals for pumps, drive belts, and other general engineering applications in the hydraulic and pneumatic industry. This O-ring is manufactured from FKM, which is a premium material and is popular within the aircraft, automotive and chemical industries. With a variety of metric and imperial sizes available to suit a wide range of applications, the O-ring also offers long life and excellent chemical resistance to most hydrocarbons, oils and fuels to aid optimum performance for the life of the O-ring.

An O-ring is a type of round or donut-shaped seal and is most commonly used to stop fluids or air passing through into another area. O-rings are normally seated between two sections and when compressed, they form a secure seal that prevents particle, vapour and fluid leakage which in turn protects and maintains pressure whilst keeping debris out, ensuring proper function and safety. They come in different sizes and materials, depending on the application they are used for, so it is important to consider what materials and fluids are going to be in contact with the seal to ensure it is the right one. These seals or gaskets are most commonly used in:

• Industrial and manufacturing applications


• Plumbing


• Hydraulics and pneumatics


• Automotive manufacturing and repair


• Power transmission technology

If the O-ring is used in the correct conditions for the material, FKM O-rings can last indefinitely

RS PRO is our own brand range and brings you a wide range of high-quality, great value products offering you more choice. Trusted by engineers all over the world, every part of every RS PRO product has been rigorously tested against demanding industry standards; they’re only given the RS PRO seal of approval if we’re confident of their exceptional quality, which means you can be confident too.

These FKM O-rings are not compatible with:

• Glycol based brake fluids


• Ammonia gas, amines, alkalis


• Superheated steam


• Low molecular weight organic acids (formic and acetic acids)

'O' Rings

'O' ring seals available in a choice of three materials to suit different applications. All 'O' rings are supplied in bags of 50. The Nitrile 'O' rings are available in both Metric and Imperial sizes. Imperial sizes are to BS1806, Metric sizes are to BS4518.