Supporting positive and negatives changes in water flows direction, flexibly meeting different operational needs, and facilitating diversified applications Equipped with an 8mm two phase four wire stepper motor, phase resistance of 22 ohms, voltages of 5V, current of 150mA, achieving high precisely quantitative output The driving voltages ranges is between 3-5V and supports single 3.7V battery power supply Low voltages may affect the motor speed and flows output Adopting an all metal casing ensures the stability and durability of the pumps, allowing for long term use in various environments Using 2.5mm silicone tubing, it has good resistance and elasticity, suitable for transporting various liquids, Manufacturer: Tsophreniq