Detector for Beta/Gamma Monitoring. Works with the AMS-4 air sampler. Model number YP11562043. Has a bracket to allow mounting to a wall, or you could place it on a shelf. You will need a cable to connect to the AMS-4. These have some shielding around the detector to reduce background. They weigh 14 lbs!
The photo is one of the units. They are all the same, with different serial numbers.