Solo is a compact, effective and easy to use single electric breast pump with rechargeable built in battery, 2-phase Expression technology and PersonalFit Flex breast shield. It has only a few parts making is easy to clean and assemble. With its intuitive 4-button interface and 9 pre-programmed settings this single electric breast pump is easy to use. With the USB type C connector on the Solo single electric breast pump, the built-in rechargeable battery charges and lasts for up to six pumping sessions when fully charged. During a feeding session, babies start by using short, fast sucks to stimulate the Milk Ejection Reflex. Once the milk begins to flow, babies change to a slower, individual rhythm. Medela's 2-Phase Expression technology mimics baby's sucking rhythms - faster to stimulate milk flow, then slower to provide optimal milk flow. With a 105-degree opening angle, soft rim and oval shape for a better fit, the PersonalFit FlexTM breast shield puts less pressure on your milk ducts resulting in an effective and comfortable pumping experience. Closed system prevents breast milk from entering the tubing, overflowing and leaking into the pump mechanism. This helps ensure that your expressed milk stays safe and clean, but also that your pump's components are protected from potential damage.