Bell & Gossett steel impeller, with a 5-3/4" outside diameter, for B&G Series PD booster pumps, specifically model PD-38. Impellers are installed on the end of the pump shaft, which spins the impeller in turn pumping water, or other liquid, throughout your system.Used On:105121 PD38S Pump 1 HP Single Phase105133 PD38T Pump 1 HP Three Phase