Linco feeding bottles are made of food grade‎,‎ heat‎-resistant Polycarbonate introduced from Germany‎,‎ which is safe and complied with the FDA‎.‎ With the pioneering injection‎-blow machine and production technique‎,‎ Linco bottles are seamless‎,‎ easy to clean‎.‎The extra‎-thickness of the bottle and the special design of the screw ring prevent the product from cracking and spilling‎.‎ All Linco bottles come with a Flow‎-adjustable nipple‎.‎ The cross‎-cut is specially designed to respond to baby‎'‎s sucking strength and will provide exactly the right flow‎.‎ Nipples do not need to be replaced as the baby grows‎.‎Nipples are made of food grade‎,‎ heat‎-resistant liquid silicone‎,‎ which is Nitrosamine‎-conformed to the FDA‎.‎ The special vent design not only prevents the Nipple from collapsing but also avoid baby from swallowing excess air during feeding‎.‎