This FKM - FPM - Viton - LT50 / AED O-Ring has a diameter of 66.4x1.78 mm and is Black in color. The hardness of this O-ring 66.4x1.78 - FKM - FPM - Viton - LT50 / AED - 90 Shore A - Black - ORS211601 is 90 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 -50 ºC to 225 ºC. O-Rings 521966 are referred to as 211601 and have a DIN 3771 size of 66.4x1.78. This item is equivalent to and has an LT50 / AED approval. The chemical name of this O-Ring is Fluorocarbon Rubber.