This bottle has the ultrasoft silicone rubber with double thickness ensures ideal softness and elasticity so the baby can latch oneasily and comfortably.The shape fits perfectly with your baby's tongue, allowing smooth tongue movement while minimising air intake The nipple's roomy base helps your baby open his mouth widely, thereby encouraging steady peristaltic motion Instructions Included. Features :- 1) Ultra-Soft Silicone 2) Streamlined Shape Bottle 3) BPA Free