Safe use - this is a new smart mug. It can be taken out of 304 stainless steel cup and washed with tap water. It can be installed after drying. Avoid the external circuit chip from contacting with water, which is safer to use. When the water is too small or the cup is tilted, the car heating cup will automatically turn off. Car heating coffee cup quiet, no noise when heating.Best choice – our coffee cups are heated, innovative and of outstanding quality, and will be for family and friends, colleagues or birthday gifts.