0 rings, also known as rubber rings and sealing rings are the most frequently used type of seal. It is due to the fact that installation of 0 rings is very easy and that they require little space. If the selected material the design of the groove are suitable, sealing based on 0 ring may play its role for a longer time (provided that the permitted temperature ranges, etc. are adhered to). The most commonly used materials for the manufacture of 0 rings are NBR (nitrile butadiene rubber), FPM (fluoroelastomer), MVQ (methyl vinyl silicone rubber), EPDM (ethylene propylene diene monomer (M-class) rubber), etc. Among the less used ones is e.g. CR (chloroprene rubber).