Nothing more than vaping pen with custom heater turned into poor man's infrared camera. Good thing - it definitely works. With some quirks. The correct size of rosin pieces for heater must me no larger than 2x3 mm or rosin will simply boil and clog everything in/around the heater. If that happen, be VERY careful on cleaning or you will break the heating element. Also room must be very well ventilated (who want lung cancer in early age). So if you want to use this for ocasional repairs when soldering in living room - think again :)