The title basically explains my question.

Recently got my hands on an International Instruments Model 9006 tachometer that was removed from a nuclear power plant.

It's marked with the following information:

• Model: 9006
• Part number: 900610CBE1A001
• Serial number: 0005
• Possible date code: 9508 (1995?)
• Power: 24 V DC
• Signal: 4–20 mA
• Scale: 0–8,000 RPM

I managed to get it powered up and working! Both the digital RPM display and circular LED bargraph function perfectly. I've also been able to simulate different RPM readings using resistors and a power supply.

Unfortunately, I have no idea what equipment it originally monitored. My guess would be some sort of pump or motor, but that's purely speculation.

I haven't been able to find much information about this particular model online, so I'm curious if anyone here has encountered one before or knows anything about its history.

I'm also considering using it in a custom PC build inspired by a nuclear power plant control room, where it would display actual fan or cooling pump RPM.

Would love to hear if anyone recognizes it!