What is this?O-Rings commonly provide a pressure and fluid seal between cylindrical shaped, overlapping mating surfaces and are commonly seen in flanges, valves, and various cylinders.What will I get?Color: BlackHardness: 70AMaterial: Nitrile Butadiene RubberTemperature Range: -4 (-20 ) to 212 (100 )Cross-Section Diameter: 2mm / 0.08-inchInner Diameter: 34mm / 1.34-inch; 35mm / 1.38-inchOuter Diameter: 38mm / 1.5-inch; 39mm / 1.54-inchPackage Contents: 10pcs x 38x34x2mm O-Rings, 10pcs x 39x35x2mm O-RingsAre there any advantages of the product?Good mechanical properties when compared with other elastomers and high wear resistance. Good resistance to many petroleum oils, greases, hydraulic fluids, mineral oil and grease.How to use it?Widely used for heat exchanger, boiler, filter, blender, coffee machine, plumbing, household electrical appliance, electronic instruments and so on.What should I notice?Please confirm the required size and material before purchase, and install it in the right place.