This bottles have been designed with the advice of breastfeeding experts, and are the perfect bottle to use alongside breastfeeding as it imitates the natural softness of a mother's breast. Product Features Soft Silicone teat, gently elongated and flexes during feeding Flex & Stretch ripples makes suction easy for babies Extra wide shaped teat makes it easy for babies to latch on. Ease-vent valve reduces air absorption making baby more comfortable. Designed to be held in the most natural position during feeding, the compact shape of Closer to Nature bottles allows baby to be closer to you. Clear with brown color Suitable for boiling, steam and cold water sterilization Temperature tolerance : 180 C Strong material, high resistance to scratch Recommended to replace your PPSU bottles for every 8-12 months BPA-free.