The three popular choices are nitrile, silicone, and Viton. I tend to use nitrile just because it's easy to work with and quick to source; I've had a lot of success with nitrile O-rings in the ...

Lee Specialties Ltd., a manufacturer of oil field equipment, shipped rubber circles known as Viton o-rings along with other equipment, to Iran on Jan. 18, 2012. Authorities intercepted the cargo ...