Ethylene propylene diene monomer (EPDM) is the compound of choice for water, steam, and polar fluids, and it is deliberately the wrong choice for petroleum oils. It offers outstanding resistance to hot water and steam to around 300°F (150°C), ozone, weathering, and brake fluids, along with excellent low-temperature flexibility down to roughly -60°F (-51°C). Moss Seal supplies both sulphur-cured and peroxide-cured EPDM, the latter for higher temperature and lower compression set. Typical uses include steam service, water treatment, potable water systems with WRAS or NSF approval, brake and hydraulic systems using glycol fluids, and outdoor equipment exposed to weather and UV.