The CD V-700 (often written as "CDV-700") is a Geiger counter employing a probe equipped with a Geiger–Müller tube, manufactured by several companies under contract to United States federal civil defense agencies in the 1950s and 1960s. While all models adhere to a similar size, shape, coloring and form-factor, there were substantial differences between various models and manufacturers over the years the CD V-700 was in production. Many of the earlier units required the use of now-obsolete high-voltage batteries, and were declared obsolete by the end of the 1970s. 
Tens of thousands of these units were distributed to US state civil defense agencies. Even though large numbers have been sold off as surplus to civilian users, many remain in use with first responders and state emergency management agencies today.