Portable constant warmer for formula brewing,Build-in 4400 mAh battery,battery powered instant warmer perfect for on the go,travel,car.Built in constant temperature chip to keep the water temperature constant. The temperature can be adjusted. The minimum temperature is 98 ° F and the maximum temperature is 113 ° F. It is perfect for brewing milk. The temperature is accurate and does not need to be measured repeatedly. Soak formula anytime, anywhere. Heating elements are food grade materials to ensure the safety of the baby.