Pentair 355122 Impeller Replacement Sta-Rite Dynamo DYNII-NI-1 HP Aboveground Swimming Pool Pump Impelled replacement Fits Pentair Sta-Rite Dynamo Aboveground swimming pool pumps model DYNII-NI-1 HP Measures 4-inch length by 2-1/2-inch height by 4-inch width