Bottle Set with Narrow Neck Options Plus, Ministarter, Dr. Browns reduces colic, belching, expectoration and gas. Characteristics: works best using the internal ventilation system Ingredients: polypropylene/silicone, BPA Free Presentation: includes: 1 250 ml narrow neck polypropylene bottle, 1 120 ml narrow neck polypropylene bottle, 2 level 1 silicone teats (0-3 months), 2 level 2 silicone teats (3-6 months) , 2 internal ventilation systems consisting of 2 parts each, brush to clean the internal system, instructions.