New GQ GMC-320 Plus Geiger Counter Nuclear Radiation Detector Data Recorder Beta Gamma x-Ray Test Equipment

If this can detect background radiation, why does a customer say it can't detect radon radiation? Beta is beta. Anyone?

Is this device emp shielded? eg, can it still be used post a nuclear blast?

Does this unit audibly click? I want a GC for field testing minerals so the tube must be near the side and otherwise suitable for prospecting.

Can it tests food?