Bell & Gossett steel impeller, 3-7/8" outside diameter, for B&G Series LD3 and 2-1/2 booster pumps. Impellers are installed on the end of the pump shaft, which spins the impeller in turn pumping water, or other liquid, throughout your system.Replaces P/N P-4-Z-1235, P-65290Used On:102218 2-1/2 IN. Pump .25 HP Single Phase102222 LD3 Pump .25 HP Single PhaseREPLACES ARMSTRONG 816305-028