The Medela Breastmilk Labeling Lids includes six breastmilk labeling lids. Select day of the week to track when breastmilk was pumped or use as a "feed by" day for other caregivers. Simple, twist-and-lock lids mark the day of the week and a.m., p.m. or midday. Compatible with Medela polypropylene breastmilk bottles. Dishwasher safe. BPA-free.