Kalrez 6375 FFKM O-Ring: Compound, Equivalents, UK Suppliers
Verified by Rachel Mayfield, Supply Chain Analyst - April 2026
Kalrez 6375 is a 75 Shore A perfluoroelastomer (FFKM) manufactured by DuPont (Chemours). It seals continuously to 275°C and is specified for chemical process and similar service. Spectrum series broad-resistance FFKM.
Specifications
| Property | Value |
|---|---|
| Compound | 6375 |
| Manufacturer | DuPont (Chemours) |
| Maximum continuous temperature | 275°C |
| Minimum temperature | -7°C |
| Hardness | 75 Shore A |
| Colour | Black |
| Material family | Spectrum series broad-resistance FFKM |
Where Kalrez 6375 is used
Kalrez 6375 is specified for: Chemical process, pharmaceutical, semiconductor wet etch, hot/cold cycling.
Limitations: Lower temp ceiling than 4079; not for high-purity semiconductor plasma.
Kalrez 6375 equivalents from other FFKM manufacturers
If Kalrez 6375 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 |
|---|---|---|---|---|
| Chemraz 555 | Greene Tweed | 240°C | 75 Shore A | approx |
| Simriz SZ481 | Freudenberg-NOK | 230°C | 75 Shore A | approx |
| Perlast G80A | Precision Polymer Engineering | 260°C | 80 Shore A | ✓ |
| Isolast J9503 | Trelleborg Sealing Solutions | 230°C | 75 Shore A | approx |
Available O-ring sizes
Kalrez 6375 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
Kalrez 6375 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
- DuPont (Chemours) — Manufacturer
- ISO 3601 O-ring sizes
- BS 1806
Frequently Asked Questions
What is Kalrez 6375 used for?
Kalrez 6375 is a 75 Shore A FFKM (perfluoroelastomer) compound from DuPont (Chemours). It is used in Chemical process, pharmaceutical, semiconductor wet etch, hot/cold cycling. Continuous service temperature: -7°C to 275°C.
What is the temperature rating of Kalrez 6375?
Kalrez 6375 has a continuous service temperature range of -7°C to 275°C. Short-term excursions above the maximum are possible but degrade service life.
What is the equivalent of Kalrez 6375?
Direct equivalents to Kalrez 6375 include: Chemraz 555, Simriz SZ481, Perlast G80A, Isolast J9503. Always confirm chemical compatibility against your specific fluid before substitution.
How much does Kalrez 6375 cost?
FFKM O-rings such as Kalrez 6375 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 Kalrez 6375 in the UK?
Kalrez 6375 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
- DuPont (Chemours) — Manufacturer
- ISO 3601 O-ring sizes
- BS 1806