Electrical & electronic items - hourmeter?

I have a requirement for running hours counter - analogue (non-tempered type) by the customer. What does non-tempered type means?

 

Tempered or tampered ?


Tampering means unauthorized resetting of the meter

Tamper proof would be a meter that cant be altered.

Perhaps this is what they ask

 

The customer means to say "tamper proof", as opposed to digital devices that can be altered without leaving traces.
The classic hour counters can also be tampered with if taken apart and reassembled, alas not without breaking the seal of the recessed screws.

 

Thanks to both of you. Now the requirement is making sense.