Master 1 Dosimeter from Russia, Radiation Detection Equipment, (MACTEP 1) spec: 0.10 to 9.99 µSv/h, 1 millirem (mrem) = 10 microsievert (µSv), Convert to Microrem: 0.10 to 9.99 µSv/h which equals 10 to 999 µR/h, 1 microsievert (µSv) = 100 microrem (µrem), readout times 100 = microrems in range of 10-999 (dozymetrem elektrycznym Master-1)

Easy to use: Slide the plastic protective tube from clip up to power up, press the white nyck button to start readings, digital readout. Slide down the plastic protective tube to power off. The plastic tube on the clip can be removed and it will power on and off as it is clipped to a pocket to be carried. To change batteries, remove the four small screws and lift up clip to replace batteries (AG12 or L1142 battery, 3 up+, 1 down-). To remove case, remove single back screw located below clip, use coin or screw driver to pry open case.