Model:4DFSW7.5-150-300-2200-AD Key Product Features Advanced Pump Construction 100% Stainless Steel: Entirely constructed from 304 Stainless Steel for maximum corrosion resistance. Water-Lubricated System: Features a water-filling lubricated rotor with high-precision top/bottom graphite bearings and thrust bearings. Durability: Double outer and inner shielding structure with internal coils made from high-temperature tolerant copper wire.