It's developed by some people from the Chaos Computer Club in Germany, problem is they basically only sell to each other and governments it's unlikely you can even buy one in North America. They cost around EUR2000+ minimum.
Their "Firewall" is a radio sensor that detects CPU activity in the baseband while the application CPU (Android) is idle, meaning shenanigans are afoot. It then shuts down the radio so essentially you end up with a temporary bricked device. You can make your own similar device, buy a used Samsung S3, build your own Android 4.1.2 or install equivalent CyanogenMod on it and this app:
https://github.com/darshakframework/darshak which accomplishes the exact same thing: warns you of stingray towers, stealth SMS, ect.
Also try thegrugq's darkmatter app, which monitors your phone's state to check if the radio has been turned off for an extended period of time, meaning it was placed in a forensics faraday bag or lab thus zeros out the /data partition or whatever you tell it to delete.
There really is no way to secure a phone because it's a pile of proprietary SoC's that run their own RTOS none of us have any access to. We only get access to the application/Android OS. If maximum privacy is your goal (you fly to China for business) then get a device with no baseband, like a Nexus 7 wi-fi only tablet, or turn on airplane mode. Install a custom rom so your carrier no longer has the keys to your build. Install macchanger to change your wireless mac often, or even better put it into Android startup init scripts before it's even brought up so no chance of leaking your MAC to every tower within range after each reboot.
Remove browser, any apps you don't need. Disable bluetooth, GPS, NFC. Install Pry-Fi
https://play.google.com/store/apps/details?id=eu.chainfire.pryfi&hl=en which has some wifi protections. Install TextSecure and Redphone. Make your own VPN:
https://www.tinfoilsecurity.com/vpn/new or rent a reliable IpSec VPN to prevent your phone from leaking metadata. Deploy false glasses, nose and moustache then cover your mouth as you walk around Shenzen discussing your intellectual property with suppliers. :P
