DHS/FEMA’s Office of CBRN is gathering market information on commercially available, gamma-detecting Personal Radiation Detectors (PRDs) with possible wireless-communication and data-transmission capabilities. The pager-sized devices should automatically monitor ambient radiation, alert users when levels exceed natural background, and help localize detected radiation sources. This RFI supports planning for a future acquisition that will include testing of the most compliant candidate solutions; responses are for information only and cannot form a binding contract. Interested contractors are responsible for their own response costs and will not receive additional information or notification of the resulting market research.