RangerEXP External 2" Geiger Muller Detector, Bluetooth with Free Observer BLE App, Protective Boot, Excellence in Radiation Detection

I have an EE background and I'm a physics nerd, but I bought this because I like gadgets; I don't have much of a practical use for it, unless WWIII. On the rare occasion that I go rock hunting, or to a gem show, it will go with me. So my review is more from a consumer standpoint.Operation and functionality are great. It's easy to use, the menus are intuitive. It has a speaker that clicks for each count; the speaker faces the front, and can be covered with tape for attenuation, or temporarily with a finger. Or you can simply disable it with the menu. The backlight has a 7 second timer, or you can set it to Always On - a setting many devices are lacking. The backlight doesn't seem to use much battery power, so I usually leave it on.It seems accurate enough. I have a couple test sources, a Zn55 gamma source and a Po210 alpha. It registers approximate expected counts on both, and it's nice to see that it does a good job of detecting alpha from the Po210. Background count is as expected. You can send this to the manufacturer, located in the US, for NIST calibration. It's only $60, so I might do that.The probe is excellent quality, very solidly built. It is all metal and has a nice cushion grip. The head contains the GM pancake tube, and it has a protective screen over the mica membrane. A simple plastic cap is included to keep stuff out, and it also functions as an alpha filter.The main unit has a plastic body and seems somehwat cheap, but it is functional. I don't like the membrane panel - they tend to wear faster. The battery compartment is the worst, it seems like it was installed as an afterthought. It's difficult to insert and remove batteries, and sometimes feels like it will break when doing so. Good thing the battery life is long.There is no provision for external power, nor a rechargeable battery pack. However, rechargeable batteries do work. The battery indicator simply shows 3 bars when full, instead of 4. I have had it powered on for about 100 hours on rechargeables, and it still shows 3 bars. Wild guess is that I will get about 300 - 500 hours, which is more than fine (specs are 800 hours with alkalines).The included cable is rather stiff, so I replaced it with a 4 foot RG174 50ohm cable. There was no change in readings with the new cable. It is much easier to use, and the extra foot of cable lets you use the probe across the body. It comes with a nice grippy soft rubber case, and also a lightweight vinyl case with a velcro back that allows one-handed use.Even though I don't like the battery compartment, stiff OEM cable, and membrane keypad, I'm still giving 5 stars because overall this is a really nice detector for the price.

Not sure if this is original. Delivered in unidentified packaging

I started to test radioactive materials with Ranger. This device has wide LCD and the indicated character becomes bigger than before. But black cable is too thick to use and hard. So I bought a thinner cable in Akihabara and used it.

Fast, light, advanced!