O-rings (sealing rings) are used for laboratory equipment, particularly glassware. An elastomer prepared from Ethylene and Propylene Monomers. Excellent resistance to water, steam, and polar solvents, as well as ozone and sunlight. Also resistant to alcohols, glycol and phospahte ester hydraulic fluid. Avoid non-polar solvents, petroleum oil, and aromatic fuels.
For more information, please see O-Ring Chemical Compatibility and O-Ring Reference