This Silicone - VMQ - MVQ O-Ring is 391x4mm and in the color Red. The Hardness of this O-ring 391x4 - VMQ - MVQ - SIlicone - FDA - EC1935/2004 - 70 Shore A - Red - ORS153864 is 70 Shore A.The alternative names of the compound are Silicone Rubber - PVMQ and they are mostly produced by Eriks - Wacker - Eastern Seals - and BlueStar. The O-ring is commonly used in and has an operating temperature range from -50 ºC to 210 ºC. O-rings 307924 are indicated as 153864 and have a DIN 3771 Size of 391x4. This item is equal to and has an FDA 21 CFR 177.2600 – EC1935/2004 Approval. The chemical name of this Oring is Vilnyl Methyl Silicone.