<h2>5-Pack Black NBR O-Rings – Oil-Resistant Nitrile Rubber Sealing Washers</h2> <p>Keep your machinery, plumbing, and hydraulic systems leak-free with these premium <strong>Black NBR (Nitrile Butadiene Rubber) O-Rings</strong>. Each pack includes <strong>5 pieces</strong> with a cross-section diameter of <strong>CS 5.7 mm</strong> and outer diameters ranging from <strong>OD 52 mm to OD 100 mm</strong>. Engineered to standard tolerances, these ring gaskets deliver a reliable, durable seal across a wide range of industrial and DIY applications.</p> <h3>Why Choose These NBR O-Rings?</h3> <ul> <li> <strong>Oil-Resistant Material:</strong> Made from high-quality Nitrile Butadiene Rubber (NBR), these O-rings offer excellent resistance to petroleum-based oils, fuels, and hydraulic fluids.</li> <li> <strong>Wide Temperature Range:</strong> Maintains sealing integrity across a broad range of operating temperatures, making them suitable for both indoor and outdoor equipment.</li> <li> <strong>Standard Dimensions:</strong> CS 5.7 mm cross-section with OD options from 52 mm to 100 mm — compatible with a wide variety of standard fittings and ports.</li> <li> <strong>Durable &amp; Long-Lasting:</strong> Resistant to aging, compression set, and wear, ensuring a long service life even under demanding conditions.</li> <li> <strong>Versatile Applications:</strong> Ideal for machinery, plumbing, hydraulic systems, pneumatic equipment, automotive components, and general industrial sealing tasks.</li> <li> <strong>Value Pack:</strong> 5 pieces per lot — stock up and have spares ready for maintenance and repairs.</li> </ul> <h3>Specifications</h3> <ul> <li> <strong>Brand:</strong> Ouling</li> <li> <strong>Material:</strong> NBR (Nitrile Butadiene Rubber)</li> <li> <strong>Color:</strong> Black</li> <li> <strong>Cross-Section (CS):</strong> 5.7 mm</li> <li> <strong>Outer Diameter (OD):</strong> 52 mm – 100 mm (multiple sizes available)</li> <li> <strong>Shape:</strong> Ring Gasket</li> <li> <strong>Standard:</strong> Standard Dimensions</li> <li> <strong>Quantity:</strong> 5 Pieces per Lot</li> <li> <strong>Country of Origin:</strong> Made in China</li> </ul> <h3>Common Applications</h3> <ul> <li>Hydraulic cylinders and pumps</li> <li>Plumbing pipe fittings and valves</li> <li>Pneumatic tools and equipment</li> <li>Automotive engines and gearboxes</li> <li>Industrial machinery and compressors</li> <li>General maintenance and repair sealing tasks</li> </ul> <h3>Related Products You May Find Useful</h3> <p>For more hardware essentials, check out these items from our store:</p> <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</a></li> <li><a href="/products/12pcs-16mm-momentary-push-button-switch-1no-metal-2-pin-self-reset">12pcs 16mm Momentary Push Button Switch 1NO Metal 2-Pin Self-Reset</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 does NBR stand for, and why is it used for O-rings?</h4> <p>A: NBR stands for Nitrile Butadiene Rubber. It is a synthetic rubber widely used for O-rings and sealing gaskets because of its outstanding resistance to petroleum-based oils, fuels, and hydraulic fluids. Its excellent mechanical properties and durability make it the go-to material for industrial sealing applications.</p> <h4>Q: What outer diameter (OD) sizes are available in this listing?</h4> <p>A: This listing covers Black NBR O-rings with a cross-section of CS 5.7 mm and outer diameters (OD) ranging from 52 mm to 100 mm. Please s