This FFKM - FFPM O-Ring is 307x5.3mm and in the color Black. The Hardness of this O-ring 307x5.3 - FFKM - FFPM - 75 Shore A - Black - Kalrez® 6375 - ORS64343 (Equivilent) is 75 Shore A.The alternative names of the compound are FFPM – Dupont Kalrez and they are mostly produced by Evolast® - Chemraz® - Simriz® - Kalrez® - Spectrum - Triazinico - Isolast® - Parofluor® - Fluorez - Perlast® - HPSealing® - Perfluor® - Polymax. The O-ring is commonly used in and has an operating temperature range from -20 ºC to 270 ºC. O-rings 537296 are indicated as 64343 and have a DIN 3771 Size of 307x5.3. This item is equal to Dupont Kalrez 6375, Freudenberg Simriz 495, Greene Tweed Chemraz 605, PPE Perlast G80A, Parker Parafluor V8910-75 and has an General Purpose (+270˚C) Approval. The chemical name of this Oring is Perfluoroelastomer.