GARFLEX® Style 8100 expansion joints feature rugged yet flexible nylon tire cord reinforcement in a molded, spherical bellows design that ensures exceptional burst pressure ratings. The streamlined flowing arch design reduces turbulence and allows smooth, quiet flow without the restricted movement you'll find with a filled arch design. Body material for all Style 8100 Expansion Joints is made of Nylon Tire Cord. Vacuum (In.Hg) and Pressure (psi) are both Application Dependent. Control units are recommended for most applications to prevent damage to the expansion joint from excessive pipe movement (sold separately).