Sorry, I no longer have these but I'm trying to see if I can figure out what model they were.
When I was about 10 or 11, my dad brought me home 2 Victoreen units, he was in the oil/gas wireline industry that did well logging. The units were very similar but I think different models. I remember one more than the other so I'll try to describe it. They didn't work as far as I could tell. I never could get a sound out of them.
The design was similar to the CDV-700. The probe snaps into the handle, but the unit was light blue. The probe connected with a BNC connector to the unit with a coiled wire that was crumbling away. The probe didn't look like the one on the CDV-700. It seemed to be longer and the tip was perfectly round. It had a shield but it slid back. There was a thumb screw on the base of the probe that you loosened to slide the shield down. To remove the tube from the probe you unscrewed the base. Inside was a GM tube with 3 pins on the bottom that plugged in. Both units as I can recall had the same probe design but the tubes were different. I tried swapping the tubes but it didn't help. The tubes were about as big around as a finger, metal with ridges going around the tube. The cap on the end appeared to be thin black plastic.
The unit itself had a knob like the CDV-700 that did X1 X10 and X100, and I think one to test the meter or battery. There was an adjustment screw on the top marked CAL.
There was a calibration sticker on it that indicated it was last calibrated in the mid 1980s. I got the unit in the late 80s or very early 90s.
I do not recall there being a test source on the side. It took 2 or 4 D batteries and had a retention clip like the CDV-700.
When taken apart it separated similarly to a CDV-700, there was a single latch to open it. I think but won't swear to it that there was a neon light bulb on the circuit board.
The dial was round as I can remember.
They got thrown out when we moved because I never got them to work. I really regret that now because I want to purchase a cheap counter for personal use and maybe these just needed a new GM tube.
I've googled victoreen units and either find CDV-700s or units that looked significantly older, nothing like what I had.
Also these units did not have a speaker in them that I could tell. You had to use a 1/4" headphone plug.
Update: I remember something about the other unit. I think it had a black handle with a grip, and the probe was held on the side. Both as I recall were Victoreen. I think I pulled the meter out of one. I have a square dial meter somewhere in my storage area made by Simpson that just says Counts on it.
Any ideas?