This FKM - FPM - Viton O-Ring has a diameter of 256x1.78 mm and is Black in color. The hardness of this O-ring 256x1.78 - FEP-FKM - FDA - ORS173218 is Shore A. Alternative names for the compound are Viton® - FKM, and it is commonly produced by Viton® - Du Pont - 3M - Solvay - Daikin. The O-Ring is typically used in and has an operating temperature range from -20 ºC to 205 ºC. O-Rings 6522800 are referred to as 173218 and have a DIN 3771 size of 256x1.78. This item is equivalent to and has an FDA approval. The chemical name of this O-Ring is Fluorocarbon Rubber.