Willow Breast Milk Storage Bags: Completely leak proof and self sealing; Willow Pump Spill Proof Breast Milk Bags offer the pumping convenience you deserve; For use with Willow 360 or 3.0 Wearable Breast Pump. Leak Proof Pumping: Patented technology offers 360 degrees of leak proof mobility for breast pumping in any position with the Willow Breast Pump, Generation 3, 2, 1. 48 Count of Willow Pump Bags: Totally hygienic to keep milk safe for your baby; recyclable, and BPA free. Holds up to 4 ounces per Bag: Pump 4 ounces at a time, or 8 ounces when double pumping; Use the Willow 3.0 app to track output in real time. Limited Warranty: 90 day limited manufacturer's warranty; Made in the USA.