Forespar Marelon Ball Valves Tailpieces A. Valves 34 . A. Marelon Ball Valves - High-strength lightweight glass-reinforced Marelon. After 11000 duty cycles they still hold 80psi of air leak-free. B. MarelonTailpieces - Hose barbs on one end. NPS pipe threads on the other. C. Marelon 90degree Elbow