Pn Series features watertight cable entrance with anti-wicking block. Permanently lubricated sealed ball bearings rated b-10 60, 000 hours. Built in motor protection. Continuous duty air filled copper wound highly efficient motor. Corrosion resistant stainless steel motor casing. Dual inside mechanical with silicon Carbide vs. Ceramic bottom faces. Ball Type air Relief Valve. Solids handling semi-vortex impeller.