Aocome plaque remover for teeth adopts the most advanced ultrasonic technology with a vibration frequency of up to 40kHz, a Rotation frequency of up to 2 million times per minute. Which Effortless crush stubborn calculus, hard tartar, and coffee or smoke stains. It also can be used for tooth surfaces with braces and retainers, and deeply hidden areas such as crevices between the teeth. 100% improve oral odor and tooth crevice blackening.