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.