Isolast J9503 FFKM O-Ring: Compound, Equivalents, UK Suppliers
Verified by Rachel Mayfield, Supply Chain Analyst - April 2026
Isolast J9503 is a 75 Shore A perfluoroelastomer (FFKM) manufactured by Trelleborg Sealing Solutions. It seals continuously to 230°C and is specified for pharmaceutical and similar service. General chemical FFKM.
Specifications
| Property | Value |
|---|---|
| Compound | J9503 |
| Manufacturer | Trelleborg Sealing Solutions |
| Maximum continuous temperature | 230°C |
| Minimum temperature | -15°C |
| Hardness | 75 Shore A |
| Colour | Black |
| Material family | General chemical FFKM |
Where Isolast J9503 is used
Isolast J9503 is specified for: Pharmaceutical, chemical process.
Isolast J9503 equivalents from other FFKM manufacturers
If Isolast J9503 isn't available, these compounds from competing manufacturers have similar chemistry and operating windows. Always verify against your actual fluid and temperature before substitution.
| Equivalent compound | Manufacturer | Max temp | Hardness | Direct match |
|---|---|---|---|---|
| Kalrez 6375 | DuPont (Chemours) | 275°C | 75 Shore A | approx |
| Chemraz 555 | Greene Tweed | 240°C | 75 Shore A | ✓ |
Available O-ring sizes
Isolast J9503 is supplied in:
- BS 1806 sizes: BS001 to BS932 (UK / EU standard, imperial-origin metric)
- AS568 sizes: -001 to -932 (US standard, dimensionally identical to BS 1806)
- ISO 3601 sizes: metric IDs from 2 mm to 670 mm with cross-sections 1.0 mm to 7.0 mm
- JIS B 2401: P, G, S series (Japanese OEM equipment)
- Custom / non-standard: built-to-print for OEM applications
For a list of sizes commonly stocked in the UK, see the BS 1806 size chart, ISO 3601 metric chart, or contact a UK seal specialist below.
UK availability
Isolast J9503 is supplied in the UK by FFKM specialists carrying multiple manufacturer lines. Lead time is typically 2-5 working days for stock sizes, 4-8 weeks for custom-moulded sizes. Use the form below to get a quote from a UK FFKM specialist.
References
- Trelleborg Sealing Solutions — Manufacturer
- ISO 3601 O-ring sizes
- BS 1806
Frequently Asked Questions
What is Isolast J9503 used for?
Isolast J9503 is a 75 Shore A FFKM (perfluoroelastomer) compound from Trelleborg Sealing Solutions. It is used in Pharmaceutical, chemical process. Continuous service temperature: -15°C to 230°C.
What is the temperature rating of Isolast J9503?
Isolast J9503 has a continuous service temperature range of -15°C to 230°C. Short-term excursions above the maximum are possible but degrade service life.
What is the equivalent of Isolast J9503?
Direct equivalents to Isolast J9503 include: Kalrez 6375, Chemraz 555. Always confirm chemical compatibility against your specific fluid before substitution.
How much does Isolast J9503 cost?
FFKM O-rings such as Isolast J9503 are typically £30 to £500 per piece depending on size, with custom or large-bore parts at the upper end. Get a current quote via the form on this page.
Where can I buy Isolast J9503 in the UK?
Isolast J9503 is supplied in the UK by independent FFKM seal specialists with multi-brand inventory. Lead time is 2-5 working days for stock BS/AS568 sizes, 4-8 weeks for custom-moulded sizes.
References
- Trelleborg Sealing Solutions — Manufacturer
- ISO 3601 O-ring sizes
- BS 1806