A perfect milk warmer for travelling. It is very suitable when travelling with stroller or car and source of power is easily accessible from powerbank or car charger or any USB connections. On top of it, the material is high quality PU leather with nice blue or pink color. If there are different sizes of milk bottles, don't worry as the warmer is adjustable to fit all sizes. Features - High Quality PU Leather - Adjustable Diameter For Any Bottle Sizes - Good Heat Preservation - Easy Travel Convenience - USB Connection Applicable To Powerbank, USB Adapter, Car USB Charger And Etc. - Safety Voltage 5V = 2A