WILLOW BREAST MILK STORAGE BAGS: Completely leak-proof and self-sealing, Willow Pump Spill-Proof Breast Milk Bags offer the pumping convenience you deserve. Each bag holds up to 4 ounces. For use with Willow 360 or 3.0 Wearable Breast Pump. PATENTED, 100% LEAK-PROOF TECHNOLOGY: Patented technology supports pumping in any position, making these breast milk storage bags ideal for moms on the move. Enjoy 360 degrees of mobility for a hands-free pumping experience. FRIDGE AND FREEZER FRIENDLY: Designed with a unique, one-way valve so milk travels without spilling, these bags can be tossed into your cooler, fridge or freezer for quick and easy storage. Simply cut the bag open to pour milk into a baby bottle for feeding. COMPATIBLE WITH WILLOW 360 or 3.0 PUMP: Pair our breast milk bags with Willow 360 or any of the previous Willow Pumps, Willow 3.0, Willow Generation 1, Willow Generation 1. TRUSTED AND TRUE: Totally hygienic and BPA free, our storage bags are covered under a 90-day limited manufacturer's warranty. Join the 300,000 moms who have brought Willow into their homes and lives.