From the #1 Spanish bottle brand. 100% silicone SX Pro Physiological nipple with anti-colic valve. SX Pro nipple is designed to help the tongue remain in the same natural position as when the baby is breast-feeding, aiding in correct positioning of the mouth, tongue & jaw. Flat, symmetrical nipple tip is centered on the bottle, offering greater adaptability & comfort as baby grows, while leaving the tongue room to rest. Long neck 20mm: reaches the junction between the hard & soft palate Ultra soft silicone with textured finish: designed to mimic the texture & consistency of the breast & nipple. Endorsed by the SEOP (Spanish Society of Pediatric Dentistry) From the #1 Spanish bottle brand, the Suavinex SX PRO physiological bottle nipple is a high quality100% silicone nipple designed to work in conjunction with the Bonhomia or Color Essence SX PRO bottle range. This revolutionary nipple is designed with respect to the baby's changing oral development and is endorsed by the SEOP (Spanish Society of Pediatric Dentistry). The physiological shape of the nipple helps the tongue remain in the same natural position as when the baby is breastfeeding, aiding in correct positioning of the mouth, tongue & jaw. Care Instructions: Wash and sterilize nipple before each use and before the first use. Do not use disinfectants that contain alcohol. To sterilize, boil 5 mins or use sterilizer. Dishwasher safe but not recommended. Recommended hand wash.Boiling method sterilization: completely submerge in boiling water for 5 minutes. Let nipple cool before using. Release any water that may have been trapped inside the nipple.