One is to heat by heating water, that is, we commonly known as the hot water bag, different from the traditional hot water bag, the electric hot water bag saves the trouble of adding water, as long as you plug in the power and wait for 10 minutes to heat, in fact, the water inside is boiled, so the general temperature will be very high.
The other is the use of lithium battery function, the internal heating sheet heating, the use of USB interface charge and discharge, similar to the warm hand mouse pad, because the lithium battery can charge and discharge function, generally can also be used as a mobile power supply. Small size, easy to carry, the temperature can reach about 50℃