When electromagnetic interference (EMI) protection and environmental sealing need to live together in one gasket, Parker Chomerics CHO-SEAL® conductive elastomers are an industry standard. Two of the most widely specified are CHO-SEAL 1298 and CHO-SEAL 1299 — engineered to deliver excellent shielding effectiveness and long-term reliability in demanding environments.
CHO-SEAL® 1299 — Low Durometer EMI Shielding
CHO-SEAL 1299 is a passivated silver-plated aluminum filled fluorosilicone elastomer that combines outstanding EMI shielding effectiveness with superior corrosion resistance against aluminum. Its lower hardness (about 45 Shore A) means it seats easily and requires less compression force while maintaining high shielding performance across a broad frequency range.
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Features:
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High shielding effectiveness up to and beyond 10 GHz
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Low compression set and easier installation due to lower durometer
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Excellent resistance to fuels, oils, and harsh chemicals
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Operating temperatures up to 200 °C
- Only Available in Molded Profiles/Sheets/O-Rings
- Does NOT meet MIL-DTL-83528 due to the soft nature of this product.
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Typical uses:
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Portable military and aerospace electronics
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Unmanned Aerial Vehicles (UAVs)
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Naval and shipboard enclosures
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Connector interface and back shell seals
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CHO-SEAL® 1298 — Proven EMI Shielding Workhorse
CHO-SEAL 1298 is also a silver-aluminum filled fluorosilicone but with a slightly higher hardness (typically ~70 Shore A). It offers the same combination of electrical conductivity and chemical/weather resistance but with additional mechanical robustness for heavier flange loads or where durability under repeated cycling matters.
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Features:
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Excellent shielding effectiveness, and corrosion resistance
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Durable yet flexible for long service life
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Available in multiple sheet thicknesses and extruded profiles
- Meets MIL-DTL-83528 Type D
- Excellent Fuel Resistance
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Typical uses:
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Avionics modules and aircraft fuselage penetrations
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Ruggedized military communication hardware
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Harsh industrial EMI sealing applications
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Precision Cutting — Die-Cut & Waterjet-Cut M83528/004 Shapes/Connector Gaskets
At NEDC, we convert CHO-SEAL 1298 and 1299 sheet stock into precision gaskets and connector gaskets. Our capabilities include:
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Die cutting for high-volume production with excellent repeatability
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Waterjet cutting (no grit) for complex shapes or low-volume builds
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Tight tolerance control to meet demanding aerospace drawings
We frequently fabricate custom EMI gaskets to M83528/004 outlines, including flat frames, D-shapes, and connector gaskets. All parts are traceable back to the certified Parker Chomerics material lot and can ship with full documentation.
Why Work with NEDC
Our combination of EMI material expertise, cutting flexibility, and certification support helps design teams reduce lead time and risk. Whether you need prototype quantities for test units or a production run of qualified gaskets, we can deliver cut parts ready to install.