This breast milk storage bag is made of good quality low density polyethylene (LDPE), which is environmentally friendly and healthy. This product is designed with double-layer sealing to prevent milk leakage. It is built with a space to record the date, time and milk volume. The product volume marking line is also accurate after the milk is stored. The bottom of this product is designed with a gusset so that it can stand firmly and save space when we store it in the refrigerator.