I have a RadStar RS300 continuos radon monitor for sale. I have used it only three times, and bought it brand new. New price was over $800.00, it does come with all cable hook ups as well as the install discs. The original calibration date is 4-12-11. would like to get at least $600 for it, but may consider a reasonable offer. I live in Loveland,CO and will ship it.
So I can have a second line of testing to see if windows or doors have been opened or a fan placed in front of the machine to lower reading. Temp change and humidity change at or around the same time as very low reading would give me an indication that the system or air movement had been tampered with.