Feature: 1. Applicable: This DIY opening source Geiger counter kit is compatible for radiation detector, please confirm the detector model before use. 2. Purpose: Nuclear radiation detection, for detecting 20mR/h‑120mR/h gamma rays and 100‑1800 off variables per points of the soft beta ray. 3. Sound and Light Alarm: This DIY detector has a sound and light alarm function, which will alarm in time when detecting abnormal data. 4. GM Tube: The tube is a tin oxide cathode, coaxial cylindrical thin wall structure (pipe wall density 50±10cg/cm2), pulse applied halogen pipe. 5. Suggestion: Please remember that building materials may contain natural radionuclides, which is why you should be careful to choose materials when building, because they will pose a great threat to your health, when moving to a new place, you must check there is no radiation. Specification: Item Type: DIY Geiger Counter Kit Material: Circuit Board Gross Weight: 168g / 5.9oz Product Size: Approx.11.3 x 6.3 x 1cm / 4.4 x 2.5 x 0.4in Purpose: nuclear radiation detection Battery: AA 1.5V dry battery (3pcs required) (shipped without battery) Parameters of matching Geiger tube: The pipe is a tin oxide cathode, coaxial cylindrical thin wall structure (pipe wall density 50 ± 10cg/cm2) pulse application halogen tube, which is used to detect 20mR/h~120mR/h, gamma rays and 100‑1800 off variables per points of the soft beta ray. Technical Parameter Diameter: Approx.10±0.5mm / 0.4±0.02in Total Length: Approx.90±2mm / 3.5±0.08in Starting Voltage: ＜350V Recommended Working Voltage: 380V Minimum Platform Length: 80V Maximum Platform Slope: 10% 80V (see M4011 below for details) Limit Operating Voltage: 550V Maximum Background Count Rate: 25 times/minute Service Life: ＞1x10^9 pulse. Package List: 1 x Mainboard4 x Red Gasket4 x Small Screw4 x Large Screw 4 x Nut 1 x Acrylic Plate1 x USB Cable1 x Geiger Tube2 x Wiring1 x Battery Box