You can change the nipple portion to different flow rates as your baby grows and gets better at bottle feeding. (abckidsinc.com)
The kit includes two nipples with different flow rates, a 7 - ounce bottle, a German silicone nipple with an anti-colic system in place, and a seal and a cap which can be used to cover the bottle when taking breaks from feeding. (tinyfry.com)
Choosing a bottle nipple may make a difference: Bottle nipples come in different flow rates - slow flow, preemie, size 1, size 2, etc.. (bluesmartmia.com)