All Thinkbaby products are free of - bisphenol-a (BPA), phthalates, nitrosamines, lead, PVC, PET and biologically harmful chemicals. The cross-cut design of the nipple eliminates spills and mimics natural breastfeeding as it requires your little one to nurse to receive fluid. The unique, anti-colic one-piece vented nipple, allows air to flow reducing gas and spit-up. The award-winning Thinkaby baby bottles transform into the sippy cup through purchase of the conversion kit. Easy to clean and dishwasher safe. Bottles made from polypropylene and nipples from extra, soft medical grade silicone. 2x stage a nipples (6 to 12 months) and 2x travel tops included.