Spectra 1 Hospital Strength Breast Pump. This S1 pump boasts powerful, yet quiet and comfortable suction. With so many great features, the Spectra S1 is designed to meet the needs of moms wanting to feel confident that they have an effective, powerful breast pump to support their supply while incorporating features to make life a little easier. Features & Benefits include: Backflow Protection technology protects breast milk and baby from bacteria, mold and viruses while pumping, 2 Phase Cycling with Let-Down Button provides adjustable suction and cycling in let-down and expression mode,Customizable pump settings to moms own response to follow her flow and find her best settings every time. Able to be used as a single or double breast pump. Pump is designed to be really quiet while in use. All components that come in touch with milk are BPA-free. Powered by an AC Adaptor or rechargeable internal battery (both included).LCD Display, timer and two-level lighting function. Included