Myers SX50H-21 Explosion-Proof Cast Iron Sump Pump 0.5 HP 1 PH 230VMyers SX50 Explosion Proof Cast Iron Sump Pump Description The Myers SX Series are heavy duty cast iron submersible sump pumps engineered for commercial and industrial dewatering applications in hazardous environments.. These pumps are designed to reduce the risk of vapor igniting the pump in hazardous environments classified as Class 1, Division 1, Group D. Myers SX50 Explosion Proof Cast Iron Sump Pump Typical Applications Class 1, Division 1, Group