Features: 1. Preset speed mode (high-mid-low speed). A gentle, pulsed stimulus begins to increase at a rate. 2. Specifically designed for patient comfort.If the patient indicates perception, simply release the button. Thestimulus stops immediately, but the numbers remain frozen onthe face for about 3 minutes. 3. Convenient to operate Peak of stimulus current reaction numerical value---80.Between 0-39, the patient feels ache and anesthesia, it meansalive teeth nerveBetween 40-79, with above-mentioned reaction, it means part ofteeth nerve dead. Over 79, no above-mentioned reaction, dead teeth nerve. 4 .The device auto-shutdown after no use of 3 minutes. (Nowasted batteries.) 5. Long and short test electrodes suit into different teethpositions. 6Autoclavable test electrodes and stainless hooks to avoid crossinfection.