2.5" multistage deep well pumps of 66 mm in diameter with increased resistance to sand. Series 2.5 STM pumps are the first multistage pumps with the diameter lower than 3" available in the Polish market. The pump capacitor has been built in the motor. Pumps available with 1.5 m long cable or with 20 m factory cable ended with a plug. The effect of increased resistance to sand is obtained due to application of "floating rotors" and selection of materials resistance to wear and tear. Pumps are equipped with thermal protection mounted on the motor winding.