Nanobebe Silicone Baby Bottles Anti-Colic 4 - 9oz 1 - 5oz Bottle Tops 23 Pcs. These bottles are designed to mimic the natural flow of a mother's breast, which helps prevent colic and promotes a healthy feeding experience for both baby and mother. The bottles are made of BPA-free plastic and have soft silicone nipples that are also anti-colic. The bottles are angled, making it easier for baby to drink and the bottles are dishwasher safe for easy cleaning. This set comes with 4 - 9oz bottles, 1 - 5oz bottle, and 23 pieces including tops.