O-rings

O-rings in stock in sizes from an inside diameter below 1 mm up to hundreds of millimetres – more than 9,400 items. They are made to DIN 3770, DIN 3771 and ISO 3601; we stock metric and inch cross-sections 1.78, 2.62, 3.53, 5.33 and 6.99 mm.

Materials: NBR 70 and 90 ShA for oils and fuels, FPM (Viton) 70 and 80 ShA for higher temperatures, EPDM 70 for water and steam including FDA grades, silicone MVQ, HNBR, polyurethane PU, CR, PTFE and FFKM. An O-ring is designated by inside diameter x cross-section, material and hardness – e.g. 25 x 2.5 NBR 70. Items in stock are shipped immediately, delivery within 1–2 days.

Frequently asked questions

How do I measure an O-ring correctly?

For an O-ring the inside diameter and the cross-section (thickness) matter, the outside diameter is not stated. Look for the size in the form inside diameter x cross-section, for example 25 x 2.5 NBR 70. An old ring may be deformed after use, so it helps to also measure the groove or the shaft the ring sits on. Typical cross-sections of AS568 inch sizes are 1.78, 2.62, 3.53, 5.33 and 6.99 mm.

Which O-ring material should I choose?

NBR is the standard for oils and fuels, roughly from −30 to +100 °C. Choose FPM (Viton) for higher temperatures up to roughly +200 °C and for many chemicals. EPDM suits water and steam, roughly up to +130 °C (peroxide-cured up to +150 °C), but it is not resistant to mineral oils or ordinary grease. Silicone MVQ withstands roughly −50 to +175 °C. For aggressive media we also stock HNBR and FFKM.

What does hardness 70 or 90 Shore A mean?

The number after the material is the hardness in Shore A. Hardness 70 is the standard for general use, harder 90 Shore A O-rings are chosen for higher pressures and smaller gaps where a softer ring could be extruded. We mainly stock NBR 70 and NBR 90 and FPM 70 and 80. When replacing a ring, it is safest to keep the hardness of the original one.

Do you have O-rings for the food industry?

Yes, we stock O-rings in EPDM 70 peroxide and silicone MVQ 70 marked FDA, some items also BfR. You will find them by the FDA marking in the product name or with the material filter in the category. Silicone rings are available for example in red or transparent. Always assess compliance with regulations for a specific use according to the requirements of your operation.

How fast can you deliver O-rings?

We stock over 9,400 O-rings to DIN 3770 and ISO 3601 in metric and inch sizes. O-rings in stock are shipped immediately and delivery takes 1–2 days. Current availability is shown directly for each size, and you can filter the category by inside diameter, cross-section and material. If you cannot find the size you need, send us the designation and we will check whether we can supply it.