Short-Term & Long-Term Radon Detectors - Combo PackPackage of one Rapidos short term radon detector and one Radtrak3 long term radon detector. Rapidos detectors are ideal for test durations ranging from 10 to 90 days, while Radtrak3 detectors are ideal for test durations ranging from 91 days to one year. Both types of detector are C NRPP approved. It is recommended that you conduct your long term test between the months of October and April when radon levels are more likely to be elevated. If your