3/16" Thick, Quattro Cross Section, Shore 65 - 75, -30 to 250°F Buna-N, also known as nitrile rubber (NBR), is made of a synthetic rubber that has anti-microbial properties and is resistant to chemicals, oils, solvents, greases and petroleum-based fluids. It is resistant to abrasions, cuts, punctures, slashes and snags.|Quattro cross-section shapes are four-lobed and feature a geometry with twice the number of sealing surfaces compared to standard O-rings. The ring is designed not to be able to twist and bend when the part moves since the cross section isn't round. They can perform at lower pressures than a standard O-ring increasing seal life.