10PCS Black NBR O-Ring CS3.1mm OD51-70mm Nitrile Rubber Seal

10-Pack Black NBR Nitrile Rubber O-Ring Seals — CS3.1mm | OD 51–70mm

Keep your machinery, plumbing, and hydraulic systems leak-free with these precision-grade NBR (Nitrile Butadiene Rubber) O-Ring seals. Each pack contains 10 pieces with a cross-section diameter of 3.1mm and outer diameters ranging from 51mm to 70mm, making them ideal as direct replacements or new installations across a wide variety of standard applications.

Key Features

• Wide Temperature Range: Engineered to perform reliably from -40°C to 120°C, suitable for both cold and high-heat environments.
• Oil & Fluid Resistant: NBR material offers excellent resistance to petroleum-based oils, fuels, and hydraulic fluids — effectively preventing leakage in demanding conditions.
• Superior Wear Resistance: Durable nitrile rubber construction stands up to repeated compression and friction, maintaining a reliable seal over time.
• Standard Ring Gasket Shape: Conforms to standard O-ring dimensions for easy, compatible fitment across machinery, plumbing fittings, valves, and more.
• Versatile Applications: Suitable for use in automotive systems, industrial equipment, plumbing joints, hydraulic cylinders, pneumatic tools, and general mechanical assemblies.
• Great Value: A pack of 10 means you always have spares on hand for maintenance or repairs.

Specifications

Shopping Tips

Need multiple sizes? Add all required size variants to your cart first and place a single order to take advantage of combined shipping savings.

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Frequently Asked Questions

Q: What does CS3.1mm mean on an NBR O-ring?

A: CS stands for "cross-section" — it refers to the thickness (diameter) of the rubber ring itself, which is 3.1mm for this O-ring. The OD (outer diameter) refers to the total outer size of the ring, available in sizes from 51mm to 70mm in this listing.

Q: What fluids and environments are these NBR O-rings compatible with?

A: NBR (Nitrile Butadiene Rubber) O-rings are highly resistant to petroleum-based oils, hydraulic fluids, fuels, water, and many industrial fluids. They are well-suited for machinery, plumbing, and automotive sealing applications within the -40°C to 120°C operating range.

Q: Can I use these O-rings for both static and dynamic sealing applications?

A: Yes. These standard NBR O-ring gaskets are suitable for both static (non-moving) sealing, such as pipe fittings and flanges, and dynamic (moving) applications such as pistons and rotating shafts, provided the operating parameters fall within the specified temperature and pressure ranges.

Q: How do I select the correct O-ring size?

A: Measure the groove or fitting where the O-ring will seat. You need the inner diameter (ID), outer diameter (OD), and cross-section (CS) to match correctly. This listing covers CS3.1mm with OD options from 51mm to 70mm — purchase multiple size options by adding them to your cart together for combined shipping.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.