SFDEJ double sphere con-nectors are always our first recommendation. The longer body has better volumetric response to sound pressure waves and provides superior sound attenuation. In seismic zones the extra movement capabilities are very important as well.
Safeflex expansion joints are molded and vulcanized in hydraulic presses. This high pressure process produces a smooth finished product with outstanding adhesion between the cover, reinforcement and tube.
Most of our competitors still use Natural Rubber impregnated Nylon tire cord between sulfur cured, EPDM covers and tubes. This construction becomes brittle with age at higher temperatures, so we changed from Nylon to Kevlar®, as Kevlar® has a higher modulus that minimizes swell and elongation, and outstanding temperature tolerance up to 250°F (121°C).