Features: Preset speed mode (high-mid-low speed). A gentle, pulsed stimulus begins to increase at a rate Specifically designed for patient comfort. If the patient indicates perception, simply release the button. The stimulus stops immediately, but the numbers remain frozen on the face for about 3 minutes. Convenient to operate Maximum stimulus--80. Between 0-40, the patient feels ache and anesthesia, alive teeth nerve. Between 40-80,with above-mentioned reaction, part of teeth nerve dead 80, no above-mentioned reaction, dead teeth nerve. The device turns itself off three minutes later after operationed (No wasted battery) Battery-operated, Standard 9-Volt battery, Extremely economical One year quality guaranteed Ce approved.