With mute, alarm, particle tone selection button, test, medium reset retest selection button, backlight can be turned on or off. Medium dosage (AVG)：Record the total dose received over a period of time and convert it into the middle display, which is characterised by small fluctuations and convenience. Press the M button to recalcate the average. (Unit: etc.) Not included: Geiger counter requires 3 AA 1.2V rechargeable batteries. High sensitivity, wide measuring range, has a long service life. --- Smaller body, larger screen, clearer measurement data and easier operation.