The Baby Brezza AirSwirl Waterless Bottle Warmer is the most advanced way to safely and evenly warm baby bottles, using the same technology used by nurses in hospitals! It warms with only hot air – not water – so there's no bacteria or scale build-up inside and bottles are 100% dry when finished. The AirSwirl safely warms breastmilk without overheating, protecting nutrients, unlike traditional warmers that use steam heat which ruins breastmilk. The machine gently rocks the bottle during warming to ensure even warming without hot spots or air bubbles. It warms so evenly and precisely, there is only 1° F temperature difference between the top and bottom of the milk during the warming process, while other warmers create 21° F temperature difference in bottles. Choose your precise warming time based on # ounces, milk type and bottle material. It's easy to use the Gentle Touch “No Press” buttons to select your settings - just tap, no need to press! The warming time counts down on the LCD display, then the warmer beeps and automatically shuts off when finished. Works with virtually all bottles and includes two rings that hold narrow neck and wide neck bottles for a universal fit. 1 year limited warranty (not valid if shipped outside the US).