This invention is a cooling insulated bottle capable of automatically cooling water at room temperature to approximately 4°C without electricity by utilizing Rubitherm RT4, a Phase Change Material (PCM).The bottle's structure is designed with four layers: the outer wall, the Phase Change Material (PCM) layer, the vacuum insulation layer, and the inner water compartment. The cooling function is realized through the principle of the PCM absorbing surrounding heat as it melts (changes phase)