Compatible with the Ember baby bottle system, sold separately Set of two extra bottles lets you stay ready for every feeding Bottle bodies hold up to 236ml (8 fl. oz.) Printed oz/ml measurements make it easy to fill the bottle precisely Food-safe, BPA-free plastic construction ensures durability and peace of mind Top-rack dishwasher-safe bottles are easy to clean Safe for sterilization in your sterilizer or in boiling water Bottle collars and nipples are sold separately