These seal is used in water purification and in R.O system and these seal is Food Grade Material.

EPDM (ethylene propylene diene monomer) is a complex yet inexpensive rubber that has a wide range of uses. It is commonly used in roofing for waterproofing, as EPDM seals nicely. It is also a common material for freezer room seals, as it is an insulator and has excellent low temperature tolerance. Specifically, EPDM operates effectively in temperatures ranging from -49F to 293F (-45C to 145C), making it perfect for applications in any temperature.

While many rubbers have high temperature resistances, only a few can deal with lower temperatures the way EPDM does. This makes it the first choice for anyone trying to create a seal in a cold environment or with cold materials. Typical applications for EPDM include electrical insulation, pond liners, tubing, solar panel heat collectors, O-rings, and more.

In addition to a large temperature tolerance, EPDM also has a wide range of chemical resistances. These include hot water, steam, detergents, caustic potash solutions, sodium hydroxide solutions, silicone oils/greases, and many other diluted acids and chemicals. It is unsuitable for use with mineral oil products, such as lubricants, oils, or fuels. For specific chemical compatibilities of EPDM. These impressive properties, combined with how inexpensive it is, make EPDM a very popular seal material.