Made of high quality, durable Glass which is BPA-Free, the wide-neck opening makes preparation of formula milk for baby simple and effortless. Features :- 1 ) Made of high quality, durable glass which is BPA-Free. 2) The nipple's roomy base helps your baby open his mouth widely, thereby encouraging steady peristaltic motion. 3) The shape fits perfectly with your baby's tongue, allowing smooth tongue movement while minimising air intake. 4) The streamlined shape makes it easy for mothers to hold and keep clean