This Silicone - VMQ - MVQ O-Ring has a diameter of 21x1 mm and is Red in color. The hardness of this O-ring 21x1 - Silicone - VMQ - MVQ - Superior - FDA - EC1935/2004 - USP Class VI - 3A Sanitary - 70 Shore A - Red - ORS223534 is 70. Alternative names for the compound are Silicone Rubber - PVMQ, and it is commonly produced by Silastic® | Elastosil® | Silopren® | NuSil® | Shin-Etsu Silicone® | Silbione® | Keisper®. The O-Ring is typically used in and has an operating temperature range from -55 ºC to 200 ºC. O-Rings 6591658 are referred to as 223534 and have a DIN 3771 size of 21x1. This item is equivalent to and has an FDA - EC1935/2004 - USP Class VI - 3A Sanitary approval. The chemical name of this O-Ring is Methyl Vinyl Siliconenrubber / Vinyl Methyl Siloxaan.