When selecting O-ring specifications, the first step is to determine the material of the O-ring: currently, in industrial parts and everyday life, O-rings are made from nitrile rubber (NR), natural rubber (NR), chloroprene rubber (CR), ethylene propylene diene monomer (EPDM), hydrogenated nitrile rubber (HNBR), silicone (ME), fluororubber, silicone fluoride, polyurethane (PU), styrene butadiene rubber (SBR), butadiene rubber, acrylic rubber, polytetrafluoroethylene, and more. Each material has its own applications and uses: some are oil-resistant, others are resistant to chemicals, and some can withstand high and low temperatures; there are also wear-resistant materials. Therefore, when choosing O-ring specifications, it is essential to know where the product will be used, what it needs to withstand, its function, lifespan, and only then can you purposefully select the required O-ring material.