The S1 Plus Hospital Strength Double Electric Breast Pump with built-in rechargeable battery provides all the features of the S2 Plus. This means that you are now able to benefit from the efficiency, power and performance of a hospital strength breast pump, without compromising on portability. Like all Spectra pumps, the S1 Plus is a closed system - a physical barrier between the milk and the pump ensures hygiene and motor performance. With a maximum suction strength of 250mmHg and the ability to be used as a single or double pump, plus a host of additional features, the S1 Plus is set to be the ultimate breast pump to support U.S. moms. The S1's completely flexible, touch button, with the S1 pump's digital controls allow you to set the pumping program to the speed and rhythm most effective for your body. The suction is adjustable in both let-down and expression mode. This quiet pump also includes a timer and night light. Gender: unisex.