Spectra S2 Plus Double Electric Breast Pump Kit has all components that come in touch with milk are BPA-free. It has 2 phase cycling with let-down button provides adjustable suction and cycling in let-down and expression mod. The backflow protection helps to protect breast milk and baby from bacteria, mold and viruses while pumping, keeps tubing dry by preventing air flow between expressed milk and pump tubing while pumping, no need to clean the narrow tubing. The spectra cooler will hold up to 6 Spectra Storage bottles.