GQ Geiger Counter GMC-080 kit Geiger Counter kit is 99% assembled and tested. Hardware is ready for PC Windows, iPhone, iPad It will accept most Geiger Tubes. The circuit board has adjustable tube voltage from 200-550V. User can adjust the voltage based on different Geiger tube installed. The main board has built-in 9V battery charging circuit. With the included high capacity rechargeable battery, you do not need to change battery every day. The board has a external DC power input for battery charging and external power supply. So, it will work continually.