Dr Brown's 8oz / 240ml Bottle Four Pack. Each bottle has a level 1 teat & vent cleaning brush.

A complete feeding system for happier babies. Created by a physician, Dr Brown's Natural Flow® is the only baby bottle with a patented internal vent system that actually helps promote good health in babies. By eliminating the vacuum and air bubbles, it helps to reduce feeding problems like colic, burping and gas. And the positive pressure created by our system is as close to breastfeeding as your baby can get. Quite simply, it looks and works unlike any other bottle.

The patented Natural Flow internal vent system is the only vent that eliminates the vacuum and the air bubbles found in most baby bottles. It allows air to enter through the teat collar without being incorporated into the breast milk or formula.
The air is then channelled through the internal vent system to the area above the breast milk or formula. 
Babies feed more comfortably because the vent allows them to nurse without fighting the negative effects of a vacuum or the discomfort of ingesting air bubbles. This helps to reduce colic, burping and wind. 
The breast milk or formula flows freely through the teat as the air is channelled to the top of the bottle. This positive pressure eliminates teat collapse, and can help reduce the build of fluid in baby's ear.