CustomControl , dual suction and speed adjustability allows moms to choose from a total of 32 combinations - for the best comfort and milk flow every time Proven Airlock Protection means our diaphragm barrier keeps the air from your pump from coming in contact with your milk while pumping. You don't have to clean the narrow tubing, and your milk stays purely yours CustomFit Flange System The Purely Yours Ultra includes three of the most commonly needed flange sizes for a good fit at your very first pumping and later as your body changes. Four other flanges sizes are also available separately