NBR 70A Nitrile O-Ring Seals CS 2–3.5mm OD 6–50mm Black Gaskets

NBR 70A Nitrile Rubber O-Ring Seals — Reliable Waterproof Gaskets for Every Application

Keep your systems leak-free with these precision-engineered NBR 70A Nitrile Rubber O-Rings. Available in a range of cross-section (CS) diameters from 2 mm to 3.5 mm and outer diameters (OD) from 6 mm to 50 mm, these black rubber ring seals are the go-to solution for plumbing, hydraulics, pneumatics, automotive, and general mechanical assemblies. Made in Mainland China.

Why Choose These O-Ring Seals?

• NBR 70A Compound: Nitrile Butadiene Rubber with a Shore A hardness of 70 offers outstanding resistance to oils, fuels, and hydraulic fluids — ideal for demanding environments.
• Wide Size Range: Cross-section diameters of 2 mm, 2.5 mm, 3 mm, and 3.5 mm paired with outer diameters from 6 mm to 50 mm give you the flexibility to tackle countless sealing tasks.
• Standard Ring Gasket Shape: Uniform, consistent geometry ensures a secure, gap-free seal every time you install one.
• Waterproof & Leak-Resistant: Engineered to prevent liquid and gas ingress in pipes, fittings, valves, cylinders, and more.
• Temperature & Chemical Resilience: Nitrile rubber handles a broad range of temperatures and resists common industrial chemicals, keeping your seals intact under real-world conditions.
• Universal Fit: Standard-dimension O-rings compatible with a wide variety of machinery, fittings, and household fixtures.

Product Specifications

Common Applications

• Plumbing pipes, taps, and faucet fittings
• Hydraulic and pneumatic cylinders
• Automotive fuel systems and engines
• Industrial machinery and pumps
• HVAC systems and compressors
• DIY home repair and appliance maintenance

Related Products You May Like

Looking for more hardware and sealing solutions? Check out these popular picks from our store:

• 10PCS Stainless Steel Self-Tapping Screws M2.2–M4.8 Phillips
• 10pcs 2-Pin Spring Wire Connectors – Quick Splice Lock Terminals
• 10/20mm Diamond Flat Grinding Wheel – Dry and Wet Use Heavy Duty

Learn more: OSHA on personal protective equipment

Frequently Asked Questions

Q: What does NBR 70A mean for an O-ring seal?

A: NBR stands for Nitrile Butadiene Rubber, a synthetic rubber compound well known for its resistance to oils, fuels, and hydraulic fluids. The "70A" refers to the Shore A hardness rating of 70, meaning these O-rings are firm yet flexible — providing a durable, long-lasting seal in both static and dynamic applications.

Q: What size O-ring do I need?

A: To choose the right size, measure the groove or fitting where the O-ring will sit. You'll need two key measurements: the cross-section diameter (CS) — the thickness of the ring itself (2, 2.5, 3, or 3.5 mm options available here) — and the outer diameter (OD), which ranges from 6 mm to 50 mm in this listing. When in doubt, refer to your equipment's technical manual or measure your existing O-ring.

Q: Are these O-rings suitable for water and hydraulic fluid applications?

A: Yes! NBR rubber is an excellent choice for water, hydraulic fluids, oils, and many petroleum-based fluids. These black nitrile gaskets are designed to provide a waterproof, leak-resistant seal in a wide range of plumbing, hydraulic, and mechanical systems.

Q: How many O-rings are included per order?

A: The quantity included per pack varies by the selected size variant. Please check the specific size/variant details before adding to your cart to confirm the quantity you will receive.

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.