This 2-pack bundle includes Dr. Brown's Anti-Colic Options Narrow Glass Baby Bottles and protective silicone sleeves to keep the bottles safe. The 8oz anti-colic bottles feature an internal vent system clinically proven to reduce colic by decreasing spit-up, burping and gas. The vent system creates a vacuum-free feeding experience closest to breastfeeding. The Level 1 nipple provides a slow, consistent flow rate so babies can feed at their own pace. The nipple shape encourages proper latching and eases switching between breast and bottle. By preserving nutrients, the vent system aids digestion for better sleep. The narrow glass bottles withstand hot/cold temperatures and are recyclable. The mint silicone sleeves protect the glass bottles from breakage during use, cleaning and sterilizing. The stretchy sleeve material makes bottles easy to grip. The see-through back panel allows viewing liquid measurements without removing the sleeve. Sleeves slide on by wetting the sleeve and bottle. Both bottles and sleeves are top-rack dishwasher safe. With anti-colic bottles for comfortable feeding and protective sleeves to prevent breaking, this bundle conveniently provides all you need for safe bottle feeding while reducing baby's colic symptoms.