Baby-quality strong and clear polycarbonate bottle cleans and sterilizes properly, unlike standard polypropylene bottles. Also the clarity makes for easy visibility of milk level and flow. Like babies bottles, the teat can be inverted with special screw-down cap to seal-off milk. Great for transporting full bottles. Soft latex teat with hollow-cone tip. Concealed non-leak air inlet prevents bottle vacuum. Bottle is 500ml capacity, marked in 50ml graduations.