Black NBR Nitrile O-Rings CS3.55mm – Seals, Gaskets & Washers

Black NBR Nitrile Rubber O-Rings — CS 3.55mm | Temperature & Wear Resistant Seals

Keep your machinery, plumbing, and mechanical assemblies leak-free with these high-quality Black NBR (Nitrile Butadiene Rubber) O-Rings. Featuring a cross-section thickness of 3.55mm, these standard ring gaskets deliver dependable sealing performance across a wide range of industrial and DIY applications. Made in Mainland China.

Why Choose These NBR O-Rings?

• Superior Material: Crafted from premium NBR (Nitrile Butadiene Rubber), offering excellent resistance to oils, fuels, and hydraulic fluids.
• Temperature Resistant: Engineered to maintain a reliable seal across a broad temperature range, from cold environments to elevated heat conditions.
• Wear Resistant: Durable construction withstands repeated compression cycles, extending the service life of your seals.
• Standard Dimensions: CS 3.55mm cross-section thickness makes these O-rings compatible with a wide array of standard fittings and housings.
• Versatile Use: Ideal for hydraulic systems, pneumatic equipment, automotive components, plumbing fittings, pumps, and general mechanical assemblies.
• Black Finish: Classic black color for easy identification in professional and workshop settings.

Product Specifications

Common Applications

• Hydraulic & pneumatic systems
• Automotive engines & fuel systems
• Plumbing & pipe fittings
• Industrial machinery & pumps
• DIY home repair & maintenance projects
• Valves, compressors, and connectors

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Frequently Asked Questions

Q: What does CS 3.55mm mean for NBR O-rings?

A: "CS" stands for Cross-Section, which refers to the thickness (diameter) of the O-ring's circular cross-section. A CS of 3.55mm means the rubber cord itself measures 3.55mm thick. This is a standard dimension used to match O-rings to specific groove and fitting sizes in hydraulic, pneumatic, and plumbing applications.

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

A: NBR (Nitrile Butadiene Rubber) O-rings are highly compatible with petroleum-based oils, hydraulic fluids, fuels, water, and many industrial lubricants. They are well-suited for automotive, industrial, and plumbing environments. However, they are not recommended for use with strong acids, ketones, or ozone-heavy environments.

Q: Are these O-rings suitable for both indoor and outdoor mechanical use?

A: Yes! These NBR O-ring seals are designed to perform reliably in both indoor and outdoor mechanical applications. Their temperature resistance and wear-resistant properties make them a dependable choice for equipment exposed to varying environmental conditions, including engine bays, outdoor plumbing fixtures, and industrial machinery.

Q: How do I choose the right O-ring size for my application?

A: To select the correct O-ring, you need to know the Inner Diameter (ID) and Cross-Section (CS) required for your specific groove or fitting. These O-rings have a CS of 3.55mm — simply match the inner diameter variant to your fitting's specifications for a secure, leak-free seal.

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.