Dr. Brown"s BPA Free Polypropylene Natural Flow 4 oz Standard Neck Bottle - 1 PkDr. Brown"s Natural Flow baby bottle was invented by a doctor and tested on his own children when they were babies, so you can rest. It is assured that this product is as safe as it is effective. This revolutionary baby bottle features a patented no vacuum design. It helps colicky babies settle down or sleep. This reduces colic, spit up, burping and gas. This helps prevent fluid in the ear. It is easy to clean, dishwasher safe. This is BPA free. Features include: •Helps colicky babies settle down or sleep •Reduces colic, spit up, burping and gas •Helps prevent fluid in the ear or no vacuum •Easy to clean, dishwasher safe •BPA free