This portable dose alarm features a high-sensitivity GM sensor (geiger counter) and advanced chip and is suitable for detecting X-ray, gm and hard . Dual display of dose equivalent rate (DER): current and cumulative. And the double alarm values can be preset, with sound and light alarm for more humanized use. Clear digital display with backlight, easy to read even in dark environments; English and Japanese switchable. 4 AAA batteries (not included), easy to install and replace batteries. Control buttons for easy operation, 3 detection units switchable (Sv/h, Gy/h, mR/h). Compact and lightweight, convenient to carry. It can be widely used in radioactive environments, factories, high altitude environments, ionising/nuclear radiation, steel/mineral/stone detection, iodine 131 detection and so on.