The dynamic inner sealing elements across the entire assortment are injection-molded from a highly cross-linked, high-density Nitrile Butadiene Rubber (NBR). This optimized elastomeric matrix is strictly engineered for standard mineral-based hydraulic oils, water-glycol fluids, and pneumatic systems operating continuously at temperatures up to 100°C. It actively resists the chemical degradation, hardening, and structural swelling that destroy standard commercial rubbers over time.

From a heavy equipment maintenance perspective, utilizing CFKS bonded seals during a hydraulic repair offers a massive engineering advantage: they require significantly lower assembly torque than traditional solid metal crush washers. Because the elastomeric NBR lip achieves the actual fluid seal, technicians do not have to yield (physically crush) solid metal to create a fluid-tight joint. This preserves the internal threads on expensive hydraulic directional control valves, cast-iron manifolds, and pump housings, completely preventing costly thread-stripping during emergency, high-stress repairs in the field.