MULTIPLE SIZES: The excellent O-ring series includes 32 common sizes, automotive O-rings metric sizes from 3mm to 50mm, a wide range of sizes and quantities to meet your needs for a long time HIGH QUALITY: The O-rings are made of high-quality nitrile rubber (NBR) and have excellent resistance to acids, gasoline, oil, UV, and heat. They can be used at sealing o-rings temperatures ranging from -30°C to +120°C CONVENIENT STORAGE: The O-rings come with a storage box that allows you to store each size of O-ring separately, making them easy to carry and store RANGE OF APPLICATIONS: One O-ring is suitable for plumbing, machinery, engines, hydraulics, piping, and pneumatics