Verified by Rachel Mayfield, Supply Chain Analyst - April 2026
Markez Z40 is a 75 Shore A perfluoroelastomer (FFKM) manufactured by Marco Rubber. It seals continuously to 316°C and is specified for steam service and similar service. Steam/amine-resistant FFKM.
Specifications
| Property | Value |
|---|
| Compound | Z40 |
| Manufacturer | Marco Rubber |
| Maximum continuous temperature | 316°C |
| Minimum temperature | 0°C |
| Hardness | 75 Shore A |
| Colour | Black |
| Material family | Steam/amine-resistant FFKM |
Where Markez Z40 is used
Markez Z40 is specified for: Steam service, hot amines.
Markez Z40 equivalents from other FFKM manufacturers
If Markez Z40 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 4079 | DuPont (Chemours) | 316°C | 75 Shore A | ✓ |
Available O-ring sizes
Markez Z40 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
Markez Z40 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.