No longer doing radon testing, I have 3 radstar a310 CRM’s from radonaway that I am looking to sell. None are within their calibration windows. I only have 2 keys. Serial numbers 876, 877, and 991. 877 fell off a stand during testing and the plastic part of the frame was damaged; it still functions, but has not been calibrated since that time. I can provide photos of any of the CRM and/or the damage if desired. 876 and 877 were originally purchased early 2021, 991 was in 2022.