Reference guide
FFKM Brands and Grades Cross-Reference
Seven companies sell perfluoroelastomer (FFKM) O-rings under seven brand names, and every line splits into the same families: a general chemical grade, a high-temperature grade, a steam grade, a high-hardness grade for gas decompression, a low-temperature grade and, for some makers, semiconductor and aerospace grades. This reference puts the brands, their owners and the maker figures on file side by side so an "or equal" comparison starts from sheets. Conquest quotes every brand below as a distributor and decides equivalence for none of them.
Who owns which brand
| Brand | Owner | Known for | Our page |
|---|---|---|---|
| Kalrez® | Qnity Electronics (the DuPont electronics spin-off, since November 2025) | The name most prints call out; the widest published grade list for chemical process and semiconductor service | Kalrez O-rings |
| Chemraz® | Greene Tweed | A universal grade that starts cold, a high-temperature grade and an oilfield grade with a published decompression test record | Chemraz O-rings |
| Simriz® | Freudenberg Sealing Technologies | Two grades listed by the maker to AMS 7257; a white grade; a food grade | Simriz O-rings |
| Perlast® | Precision Polymer Engineering Ltd, part of IDEX | Acid and amine resistance with low permeability on the sheet on file (G75B); the maker names G75TX and G75M alongside it | this page |
| Isolast® | Trelleborg Sealing Solutions | PureFab® grades for semiconductor chambers, XploR® grades for oil and gas, J-series grades with FDA, USP Class VI and 3-A listings | this page |
| Parofluor® | Parker Hannifin | The FF-series grades sold alongside Parker's own O-ring handbook | this page |
| Markez® | Marco Sealing Solutions | The FFKM line sold under Marco Sealing Solutions' own name; no maker sheet on file here | this page |
A brand is one maker's polymer, compound and molding. Two brands in the same family are not the same part, and no maker publishes an equivalence table for a competitor's grade that a buyer should rely on. Where one appears in a maker's literature it is that maker's marketing, and we do not reproduce it.
The grade families across the brands
The table names one representative grade per maker in each family where a maker sheet is retained here, with the maker's own low and high figures. A blank cell means the maker publishes a grade in that family but no sheet for it is on file, or the maker positions no grade there. The families are our grouping of the makers' own descriptions.
| Family | Kalrez (Qnity) | Chemraz (Greene Tweed) | Simriz (Freudenberg) | Perlast (PPE) | Isolast (Trelleborg) | Parofluor (Parker) |
|---|---|---|---|---|---|---|
| General chemical | 6375: -20 to 275 C, 75 A | 505: -30 to 230 C, 75 A | 485: -7 to 230 C, 75 A | G75B: -15 to 325 C max, 275 C continuous, 85 A | J9503: -19 to 250 C, 75 A | FF350-75: -15 to 320 C, 74 A |
| High temperature | 7075: -18 to 327 C, 75 A | 615: -18 to 324 C, 80 A | 498: -6 to 325 C, 80 A | G75B (see above) | PureFab JPF40: to 327 C, 75 A | FF350-75 (see above) |
| Steam and hot water | 7375: -20 to 300 C, 77 A | 605: -20 to 260 C, 80 A | 495: -7 to 230 C, 75 A | J8290: to 290 C, 75 A | ||
| Rapid gas decompression | 0090: -27 to 250 C, 95 A | 526: -20 to 250 C, 97 A | 134: -15 to 230 C, 90 A | XploR 9523: -40 to 250 C, 90 A | ||
| Low temperature | 0040: -42 to 220 C, 70 A | 505 (see above) | 481: -30 to 230 C, 70 A | XploR 9523 (see above) | ||
| Semiconductor | 9100: to 300 C; 8900: to 325 C | 486 (white): -7 to 230 C, 75 A | PureFab JPF10: to 310 C; JPF20 and JPF30: to 300 C; JPF21: to 320 C | |||
| Food, pharmaceutical, aerospace listings | 484 (3-A, FDA, USP VI); 501 and Z7257 (AMS 7257) | J9515 and J9516 (FDA, USP VI, 3-A): -10 to 250 C, 75 A |
Two lines carry the extremes on the sheets on file. Kalrez 0040 is rated by its maker down to -42 C and Isolast XploR 9523 down to -40 C, while Kalrez 7075 is rated to 327 C and Isolast PureFab JPF40 to 327 C at the hot end. Perlast G75B is rated by its maker to 325 C as a maximum and 275 C for continuous use, which is the one sheet here that publishes both numbers. Parofluor FF350-75 is rated from -15 C to 320 C on the Parker sheet. Markez grades are named by Marco Sealing Solutions on its own pages; no maker sheet for them is retained here, so this table carries no figure for them.
What an "or equal" needs
An "or equal" on a print is an engineering decision, and it belongs to the print's owner. The comparison that supports it is the maker sheets for the two grades, read in the same family: the temperature figures, the hardness, the compression set at the temperature that matters, the media the maker lists for and against, and any listing the print depends on (AMS 7257, NORSOK M-710, FDA, USP Class VI, 3-A). A general grade from one maker is not automatically the equal of another maker's general grade; across the sheets on file the low figures of the general grades alone spread from -7 C to -30 C. Conquest quotes the equal you approve, sends the maker's sheet with the quote, and never decides equivalence for you.
What to send with the request
The AS568 dash number or the inside diameter and cross-section; the brand and grade the print names, or the family if it names none; whether an equal is allowed and which one your engineering has approved; the medium, the temperature and the pressure; and any listing the part must carry. The quote names the maker, the grade and the sheet, and the certificate comes from the maker with the part. The FFKM material page covers the chemistry and the branded vs generic FFKM guide covers what a brand buys you.
Kalrez is a trademark of Qnity Electronics; Chemraz is a trademark of Greene Tweed; Simriz is a trademark of Freudenberg Sealing Technologies; Perlast is a trademark of Precision Polymer Engineering, part of IDEX; Isolast, PureFab and XploR are trademarks of Trelleborg Sealing Solutions; Parofluor is a trademark of Parker Hannifin; Markez is a trademark of Marco Sealing Solutions. No affiliation or endorsement is implied.
Sources
- Parker O-Ring Handbook ORD 5700, service temperature table, page 7-2 (FFKM -26 C to 320 C), read 2026-09-25
- Kalrez CPI Product Selector Guide KZE-A40126, Qnity Electronics (formerly DuPont), November 2022, read 2026-09-14
- Kalrez Semiconductor Product Selector Guide KZE-H88232, DuPont, February 2012, read 2026-09-14
- Chemraz 505, 615, 526 and 605 product brochures, Greene Tweed, 2018, read 2026-09-14
- FFKM Simriz brochure 71 US 011, Freudenberg-NOK Sealing Technologies, read 2026-09-14
- Perlast G75B datasheet, Issue 4, Precision Polymer Engineering, read 2026-09-14
- Advanced Isolast Capabilities brochure, Trelleborg Sealing Solutions, 2021, read 2026-09-14
- Parofluor FF350-75 datasheet, Parker O-Ring Division, October 2003, read 2026-09-14
- Marco Sealing Solutions, Markez O-rings page (grades named), read 2026-09-14
- Parker O-Ring Handbook ORD 5700, section 2.2.10, read 2026-09-14
Reviewed by Grant Midstokke, Conquest Seal Corporation. Last updated September 2026. Material ranges are the published references named beside them; the compound datasheet and your application govern the final choice.
Frequently asked questions
Which FFKM brand is best?
None of them is best across the board. Each maker's line splits into the same families, and the right part is the grade whose sheet fits your medium, temperature and pressure. The grade figures on this page are where the comparison starts.
Can Conquest tell me if a Chemraz grade equals a Kalrez grade?
No. Equivalence is your engineering's decision on the two maker sheets; Conquest supplies both brands, puts the sheets side by side and quotes the part you approve.
Why are there no figures for Markez?
Because no maker sheet for a Markez grade is retained here. Marco Sealing Solutions publishes figures on its own pages; when a sheet is on file the figure will be added.
Which brands have aerospace-listed grades?
Freudenberg lists Simriz 501 and Z7257 to AMS 7257 in its brochure. Other makers list grades to the document in their own literature; a print that names AMS 7257 needs the maker's certificate for the grade it ships.
Which brands have a semiconductor line?
Kalrez (the 8000 and 9000 series with UP cleaning), Isolast (the PureFab grades) and Simriz (the white 486 and the 508 grades named by the maker). The figures on file are maximum temperatures only.
What does the family figure mean when every grade differs?
The Parker handbook family range, -26 C to 320 C, is the figure that applies before a grade is named. Once the print names a grade, that grade's sheet governs, and the sheets on file run from -42 C to 327 C across the brands.
Related guides
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