Helps transition from bottle to sippy, great for infants to toddlers!! Use it on-the-go, insulated and tested accross the board for safety. Not easily breakable and suitable for any beverage. This is a great piece, use it until the nipple shows wear and then replace only that. Let's combat the 20-plastic-bottles-and-cups-in-the-cabinet-syndrome together! Completely safe, #304 food grade 18/8 stainless steel. Phthalate, PVC & BPA free. CPSIA certified.