... strong ,so that the noise is very small.2.Ergonomic Design, Feel Comfortable In the design, the weight of top and bottom is ... according to the sterilization.Battery and charger must not be sterilized.2、Before the operation,the battery must be filled,and the filled battery ... use,must to be cleaned,then remove the battery.And don’t put the battery and the handpiece together.Do not drop impact , ...