A firm, rugged, flexible, Nitrile Elastomer - closely approximate the perfect hydraulic seal. For installation, simply stretch them over large diameters, or fold them for insertion into small diameters. No adhesives, no special tools necessary. Temperature range - 20 to 400F (-29 to 204C) with limited serviceability up to 600F (315C). Durometer reading: 70A. Color: Black.