Made of high-quality rubber, these O-rings are durable and have a longer service life. They have good abrasion resistance, elasticity, tensile strength, and elongation. There are many different sizes of O-rings in this set, which can meet your different needs. Total 300 pieces, so you don't have to worry about running out of O-rings for a while. They can be widely used for sealing cylinders, automobiles, valves, chemical pipelines, rollers, etc.