Vented Feeding Bottles :triple-vented cap delivers unrestricted milk flow to prevent colic, spit-up, burping, gas, and fluid in the ear. Making feeding a happier time for all. Plus, our patented leak-proof filter system means your bottle will never leak. Triple-vented to prevent colic, spit-up, burping and gas. Contain less parts than other fully vented bottles, which means easier to use and clean. Eliminates Nipple collapse. Leak-Proof Guaranteed!