<h2>20-Pack NBR Nitrile O-Ring Seals — CS 3.1mm | OD 31–40mm</h2> <p>Keep your plumbing, hydraulic, pneumatic, and mechanical systems leak-free with these heavy-duty <strong>NBR (Nitrile Butadiene Rubber) O-Ring Seals</strong>. Each pack contains <strong>20 identical rings</strong> in your chosen outside diameter, making it easy to stock up on the exact size you need for maintenance, repairs, or new installations at home or in industrial/factory settings.</p> <h3>Key Specifications</h3> <ul> <li> <strong>Material:</strong> NBR (Nitrile Butadiene Rubber)</li> <li> <strong>Color:</strong> Black</li> <li> <strong>Cross-Section (CS) Thickness:</strong> 3.1 mm</li> <li> <strong>Outside Diameter (OD) Options:</strong> 31 / 32 / 33 / 34 / 35 / 36 / 37 / 38 / 39 / 40 mm</li> <li> <strong>Inside Diameter (ID):</strong> 24.8 / 25.8 / 26.8 / 27.8 / 28.8 / 29.8 / 30.8 / 31.8 / 32.8 / 33.8 mm (corresponding to OD)</li> <li> <strong>Quantity:</strong> 20 pcs per pack</li> <li> <strong>Shape:</strong> Standard Ring Gasket</li> <li> <strong>Standard:</strong> Standard metric sizing</li> </ul> <h3>Why Choose NBR O-Rings?</h3> <ul> <li>✅ <strong>Oil Resistant</strong> — Excellent performance in contact with petroleum-based oils and fuels</li> <li>✅ <strong>Wear Resistant</strong> — Durable rubber compound holds up under repeated compression and movement</li> <li>✅ <strong>Waterproof</strong> — Creates a dependable watertight seal in pipes, fittings, and valves</li> <li>✅ <strong>Temperature Resistant</strong> — Maintains sealing integrity across a wide temperature range</li> <li>✅ <strong>Versatile Use</strong> — Ideal for air conditioning units, hydraulic systems, pneumatic equipment, plumbing, and general mechanical assemblies in both home and factory environments</li> </ul> <h3>Applications</h3> <p>These NBR sealing rings are suited for a wide variety of uses including:</p> <ul> <li>Air conditioning and HVAC fittings</li> <li>Hydraulic and pneumatic connectors</li> <li>Plumbing pipe joints and faucet repairs</li> <li>Industrial machinery and factory equipment</li> <li>Automotive fluid systems</li> <li>General-purpose mechanical sealing at home or in the workshop</li> </ul> <p><strong>Made in Mainland China.</strong></p> <h3>Related Products You May Like</h3> <ul> <li><a href="/products/stainless-steel-self-tapping-screws-m2-2-m4-8-phillips-wood-hinge">10PCS Stainless Steel Self-Tapping Screws M2.2–M4.8 Phillips</a></li> <li><a href="/products/10pcs-2-pin-quick-splice-spring-wire-connectors-lock-terminals">10pcs 2-Pin Spring Wire Connectors – Quick Splice Lock Terminals</a></li> <li><a href="/products/10-20mm-diamond-flat-grinding-wheel-dry-and-wet-use-heavy-duty-concrete-grinder-wheel-blue-vacuum-brazed">10/20mm Diamond Flat Grinding Wheel – Heavy Duty Concrete Grinder</a></li> </ul> <p>Learn more: <a href="https://www.osha.gov/personal-protective-equipment" target="_blank" rel="noopener">OSHA on personal protective equipment</a></p> <h3>Frequently Asked Questions</h3> <h4>Q: What sizes are available in this NBR O-ring pack?</h4> <p>A: Each pack contains 20 pieces of the same outside diameter. You can select from OD sizes of 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 mm — all with a consistent 3.1 mm cross-section thickness.</p> <h4>Q: Are these O-rings suitable for use with oils and fuels?</h4> <p>A: Yes. NBR (Nitrile Butadiene Rubber) is specifically formulated to resist petroleum-based oils, fuels, and hydraulic fluids, making it one of the most widely used materials for sealing in automotive, hydraulic, and industrial applications.</p> <h4>Q: Can these gasket rings be used in both home and industrial settings?</h4> <p>A: Absolutely. These standard-metric NBR O-rings are well-suited for household plumbing repairs, air conditioning units, and DIY projects, as well as for factory and industrial machinery maintenance requiring reliable, leak-free seals.</p> <h4>Q: How do I choose the correc