This FFKM - FFPM O-Ring is 18 x 4mm and in the color Black. The Hardness of this O-ring 18x4 FFKM - FFPM - FDA - USP Class VI - 3A Sanitary - Kalrez 6230 - 70 Shore A - Black - ORS220903 (Equivalent) is 70 Shore A.The alternative names of the compound are FFPM – Dupont Kalrez and they are mostly produced by 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 -25 ºC to 270 ºC. O-rings 656918 are indicated as 220903 and have a DIN 3771 Size of 18 x 4. This item is equal to Dupont Kalrez 6230, Freudenberg Simriz 491 and has an Approval. The chemical name of this Oring is Perfluoroelastomer.