I have 14 E-Perm boxes in good condition with S Chambers, two Rad-Elec monitoring devices, and one electret reader to sell. The s chambers have electrets but I do not know the current levels.
Reader calibrated? How much?
If you can get the voltages of the electrets, I might be interested in them.
I can get the readings but the Reader has not been calibrated in a couple of years since we moved to AirThings… The reader does zero out on the reference electret but the other two reference electrets have lost some over the last few years. If you are still interested I will get the readings. Serial Numbers etc.
No. I have an older model that I am keeping for demos/training (or until InterNACHI wants to buy it for the antique collection ;-).
The newer is SPER 1E. Reads the zero correctly be the reference(s) have lost a bit since last certification which lapsed in 2022.
What is your offer. It included the nitrogen valve / kit etc. (If you need it or not it ships as a kit 
Did you want be to get the current readings?
If you can get them , I might be interested in the electrets