MORE SAFETY - it adopts the rotary transformation of environment-friendly polypropylene, is resistant to high temperature, corrosion and deformation, and is safe to prevent leakage. The outer side adopts precision welding sealing, and the edge is smooth without hurting hands, so it is more reliable. A small body will take up almost no space when it is not filled with water, and when you need it, simply fill it with hot water, which will bring you great warmth.