Glass, silicone, and plant-plastic help avoid harmful chemicals—Liquids touch only borosilicate glass and 100% LFGB silicone, with Sprout Ware® plant-based plastic collar and travel cap. All parts are made without PVC and hormone-disrupting BPA, BPS, BPF, BFDGE, NOGE or BADGE additives. Angled neck and vented nipple support healthy digestion and comfort—Allows baby to sit more upright and easier to hold when feeding and helps reduce the risk of swallowing air that can lead to colic, gas, and digestive discomfort. Flexible, variable-flow nipple supports continuous latch—X-cut, variable flow nipple allows baby to regulate flow and flexes to mimic and complement breast feeding without nipple confusion.