BREASTMILK SAFETY IS OUR UTMOST PRIORITY 1. Made of food grade BOROSILICATE GLASS which has very low coefficients of thermal expansion, making it thermal shock resistant (can be boiling sterilized, freezer & oven safe); is also known to be chemically stable. 2. Bottles contain no harmful chemicals, NO PLASTIC TASTE leaching into your baby's milk (penetration of toxic substance leads to plastic taste). 3. CPC Certified Food Grade 4. Wide neck glass bottles are also easier to clean and use. 3-IN-1 WIDE NECK BOTTLES FOR PUMPING, STORING & FEEDING 1.The clear sealing disk can be replaced with nipples, so a mom can pump, store and feed from the same glass bottle to reduce breast milk transfers and preserve precious breast milk. 2. The bottles work perfectly with most wide neck pumps, like Spectra and Philips. 3. For narrow neck pumps: such as Medela, Bottle Convertor is included in the product package. LEAKPROOF AND EASY TO CLEAN 1. The screw-on lid and sealing disc are specially designed to prevent the bottle from leaking. Ideal for freezing, travel, flights and camping. 2. Clearly marked measurement for breast milk storage and feeding, not easy to be washed off. 3. Not only is glass bottle healthier for baby to drink from, but also it is much easier to clean than plastic because the glass bottle is less likely to develop scratches that hold on to residue and odors. ATTENTION 1. For 6oz bottes, the FREEZER LINE is 5 OZ. Please do NOT put more than 5oz of milk into the bottle if you want to freeze the milk. 2. For 8oz bottes, the FREEZER LINE is 7 OZ. Please do NOT put more than 7oz of milk into the bottle if you want to freeze the milk. 3. A free Matyz bottle convertor (for narrow-mouth devices) is included. Please keep it for future use (it will turn out to be useful).