<h2>50-Pack Black NBR O-Ring Seals — Reliable Nitrile Rubber Gaskets for Machinery &amp; Plumbing</h2> <p>Keep your systems leak-free with this value pack of 50 black NBR (Nitrile Butadiene Rubber) O-ring seals. With a cross-section of 1.8mm and inner diameters ranging from 4.5mm to 6.9mm, these standard-size ring gaskets are engineered for dependable sealing performance across a wide range of industrial, mechanical, and plumbing applications. Made in Mainland China.</p> <h3>Key Features</h3> <ul> <li> <strong>Oil Resistant:</strong> NBR nitrile rubber compound effectively resists petroleum-based oils and fuels, making these O-rings ideal for hydraulic and lubrication systems.</li> <li> <strong>Wide Temperature Range:</strong> Operates reliably from -40°C to 120°C (-40°F to 248°F), handling both cold and high-heat environments with ease.</li> <li> <strong>Excellent Wear Resistance:</strong> Durable rubber construction maintains its shape and sealing integrity even under repeated use and compression.</li> <li> <strong>Standard Sizing:</strong> CS 1.8mm cross-section with inner diameters from 4.5mm to 6.9mm — compatible with many standard fittings, valves, and connectors.</li> <li> <strong>Versatile Applications:</strong> Suitable for machinery, plumbing, hydraulics, pneumatics, automotive systems, and general-purpose sealing tasks.</li> <li> <strong>Great Value:</strong> 50 pieces per lot means you always have a spare on hand for quick repairs and maintenance.</li> </ul> <h3>Specifications</h3> <table> <tbody> <tr> <td><strong>Material</strong></td> <td>NBR (Nitrile Butadiene Rubber)</td> </tr> <tr> <td><strong>Color</strong></td> <td>Black</td> </tr> <tr> <td><strong>Cross-Section (CS)</strong></td> <td>1.8mm</td> </tr> <tr> <td><strong>Inner Diameter (ID)</strong></td> <td>4.5mm – 6.9mm</td> </tr> <tr> <td><strong>Shape</strong></td> <td>Ring Gasket</td> </tr> <tr> <td><strong>Standard</strong></td> <td>Standard</td> </tr> <tr> <td><strong>Quantity</strong></td> <td>50 PCS per Lot</td> </tr> <tr> <td><strong>Operating Temperature</strong></td> <td>-40°C to 120°C</td> </tr> <tr> <td><strong>Origin</strong></td> <td>Made in Mainland China</td> </tr> </tbody> </table> <h3>Shopping Tip</h3> <p>Need multiple sizes? Add all required O-ring sizes to your cart first, then check out in a single order — combined shipping discounts apply automatically at checkout.</p> <p><strong>Note:</strong> Due to differences in monitor display settings and lighting, the actual product color may vary slightly from images shown.</p> <h3>You May Also Like</h3> <ul> <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/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/1000d-tactical-edc-bag-military-ammo-pouch-hunting-wash-bag-dump-pouch-portable-tool-storage-handbag-compatible-military-utility">1000D Tactical EDC Bag Military Ammo Pouch Portable Tool Storage Handbag</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 material are these O-rings made from, and why does it matter?</h4> <p>A: These O-rings are made from NBR (Nitrile Butadiene Rubber), a synthetic rubber known for its excellent resistance to petroleum-based oils, fuels, and hydraulic fluids. NBR is the go-to material for sealing applications in machinery and plumbing where oil or fuel contact is expected.</p> <h4>Q: What sizes are included in the 50-piece lot?</h4> <p>A: Each lot contains 50 black NBR O-rings with a cross-section (CS) of 1.8mm and inner diameters (ID) ranging from 4.5mm to 6.9mm. Please check your specific size re