This HNBR O-Ring has a diameter of 253 x 3.5 mm and is Black in color. The hardness of this O-ring 253x3.5 - HNBR - 70 Shore A - Black - ORS186634 is 70 Shore A. Alternative names for the compound are Hydrogenated Nitrile Butadiene Rubber, and it is commonly produced by Eriks - Wacker - Eastern Seals - and BlueStar. The O-Ring is typically used in and has an operating temperature range from -25 ºC to 150 ºC. O-Rings 881998 are referred to as 186634 and have a DIN 3771 size of 253 x 3.5. This item is equivalent to and has an FDA approval. The chemical name of this O-Ring is Hydrogenated nitrile rubber.