Tin oxide cathode, coaxial cylindrical thinshell structure (wall density of 5010cg/cm2), pulse applied type halogen tube. Support provide the detection -Ray of 20mR/h-120mR/h and soft -Ray in r-ange of 100-1800 decay/minutesCM2. The ambient medium temperature is from -40C to 55C. Easy installation, it can be installed on the geiger counter without need tools. Comes with one PVC tube for convenient transmission. A perfect replacement accessory for IOT--v1.1 IOT open-source geiger counter -tube. Name: J305 Geiger -Tube Working temperature: -40 to 55 Minimum plateau length: 80V Max plateau slope rate: 10%/80V limiting operating voltage: 550V Max background count rate: 25 times/min Colour:transparent Material:Glass Package Contents: 1 x J305 Geiger tube 1 x ion chamber Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.