014 Viton O-Ring, 75A Durometer, Round, Brown, 1/2" Id, 5/8" Od,, Pack Of 100 This O-ring is made of brown Viton and has a durometer of 75A. It has a round cross-section and can be used across a wide temperature range (-15 degrees F/-26 degrees C to 400 degrees F/205 degrees C). Designed for use in a wide variety of sealing applications, this Viton O-ring meet standards defined by Aerospace Standard AS568A, which is the Aerospace Size Standard for O-rings. Viton (fluorocarbon elastomer) has high heat, fuel, and chemical resistance, and is compatible for use with non-flammable hydraulic fuels, silicone oil, chlorinated hydrocarbons (trichlorethylene), fuels, aromatic hydrocarbons (benzene) and aliphatic hydrocarbons (propane), as well as high vacuum environments, ozone, and weathering. Viton is vulnerable to low molecular organic acids, ammonia gas, alkalis, amines, glycol-based brake fluids, and super-heated steam. The durometer hardness of this Viton O-ring is 75A. Durometers measure the hardness of a material and its resistance to permanent indentation. A higher durometer value indicates greater resistance to indentation. On a scale of 0 to 100, a value of 0 indicates that a sample was completely penetrated, while a value of 100 shows no indentation in the sample. The letter following the number identifies the shore scale, which is either shore A or D. Shore A is used for softer plastics, while shore D is used for harder plastics. O-rings provide a pressure and fluid seal between cylindrically shaped, overlapping mating surfaces and are commonly seen in engines, faucets, flanges, valves, and various cylinders. They are circular in shape, with a round cross section, and a hole in the center, similar to a doughnut. O-rings are available in various AS568A dash sizes, which is the standardized sizing for O-rings, and defines the nominal inside diameter (ID), outer diameter (OD), and cross-sectional (CS) diameter of an O-ring. Made of Viton (fluorocarbon elastomer) for use with a variety of chemicals and fuels Durometer (hardness) of 75A for resistance to penetration Round cross-section to provide a seal between cylindrical overlapping surfaces For use across a wide temperature range from -15 degrees F/-26 degrees C to 400 degrees F/205 degrees C Meets standards defined by Aerospace Standard AS568A