<h2>20PCS Black NBR Nitrile Rubber O-Rings — Reliable Sealing for Machinery, Plumbing &amp; Hydraulic Systems</h2> <p>Keep your systems running leak-free with this 20-piece set of <strong>Black NBR (Nitrile Butadiene Rubber) O-Rings</strong>. Featuring a cross-section diameter of <strong>CS 3.5mm</strong> and outer diameters ranging from <strong>OD 36mm to 50mm</strong>, these standard-size gasket washers are engineered for durable, oil-resistant sealing in a wide range of industrial and domestic applications.</p> <p>Made in Mainland China.</p> <h3>Key Features</h3> <ul> <li> <strong>Material:</strong> High-quality NBR (Nitrile Butadiene Rubber) — excellent resistance to oils, fuels, and hydraulic fluids</li> <li> <strong>Cross-Section (CS):</strong> 3.5mm for a reliable, consistent seal</li> <li> <strong>Outer Diameter (OD):</strong> Available from 36mm up to 50mm — fits standard machinery and plumbing fittings</li> <li> <strong>Quantity:</strong> 20 pieces per lot — perfect for stocking up or completing a repair job</li> <li> <strong>Shape:</strong> Ring Gasket — standard form factor for universal compatibility</li> <li> <strong>Oil-Resistant:</strong> NBR compound withstands petroleum-based oils, hydraulic fluids, and greases</li> <li> <strong>Temperature Range:</strong> Suitable for a broad range of operating temperatures in industrial environments</li> <li> <strong>Colour:</strong> Classic black for easy identification in mechanical assemblies</li> </ul> <h3>Ideal Applications</h3> <ul> <li>Hydraulic and pneumatic systems</li> <li>Plumbing pipe joints and fittings</li> <li>Pumps, valves, and compressors</li> <li>Automotive and industrial machinery</li> <li>General mechanical sealing and gasketing</li> </ul> <h3>Specifications</h3> <table> <tbody> <tr> <td><strong>Material</strong></td> <td>NBR (Nitrile Butadiene Rubber)</td> </tr> <tr> <td><strong>Cross-Section (CS)</strong></td> <td>3.5mm</td> </tr> <tr> <td><strong>Outer Diameter (OD)</strong></td> <td>36mm – 50mm</td> </tr> <tr> <td><strong>Colour</strong></td> <td>Black</td> </tr> <tr> <td><strong>Quantity</strong></td> <td>20 PCS / Lot</td> </tr> <tr> <td><strong>Standard</strong></td> <td>Standard</td> </tr> <tr> <td><strong>Country of Origin</strong></td> <td>Mainland China</td> </tr> </tbody> </table> <h3>You May Also 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-durable-gold-blade-nut-metal-universal-trimmer-accessories-anti-loosening-line-left-hand-thread-replacement-parts-1">10pcs Durable Gold Blade Nut Metal Universal Trimmer Accessories Anti-Loosening Line Left Hand Thread Replacement Parts</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 Dry and Wet Use Heavy Duty Concrete Grinder Wheel</a></li> </ul> <p>Learn more: <a href="https://www.osha.gov/hand-power-tools" target="_blank" rel="noopener">OSHA guidance on hand and power tools</a></p> <h3>Frequently Asked Questions</h3> <h4>Q: What is the cross-section and outer diameter range of these NBR O-rings?</h4> <p>A: These nitrile rubber O-rings have a cross-section (CS) of 3.5mm and are available in outer diameters (OD) ranging from 36mm to 50mm, making them compatible with a wide variety of standard machinery, plumbing, and hydraulic fittings.</p> <h4>Q: Are these O-rings suitable for use with oil and hydraulic fluids?</h4> <p>A: Yes. The NBR (Nitrile Butadiene Rubber) material is specifically formulated for excellent resistance to petroleum-based oils, hydraulic fluids, and greases, making these gaskets ideal for hydraulic systems, pumps, valves, and industrial machinery.</p> <h4>Q: How many O-rings are included in one lot?</h4> <p>A: Each lot contains 20 pieces,