... in the bottom balances the pressure inside and outside the bottle; more healthy, safer, no-toxic and odorless, heat-resistant ... sterilizationBottle:food level PC material, one-time injection blow moulding; bottle is transparent, Light weight, smooth inside, easy to wash, ... mother and the baby; no-toxic,safe, hygienic. Double-handle:new extremely wide double-handle design, develop babys ability of grap