In first season episode The Naked Time, Commander Spock conspicuously uses this unique instrument to scan and analyze conditions at the frozen laboratory on unstable planet Psi 2000. The same device had been used briefly by Scotty in earlier first season episode The Enemy Within, where it was simply described as a scanner, and subsequently also glimpsed in second season episodes Obsession and The Doomsday Machine.
Like the original prop, this replica is a repainted Nuclear-Chicago model 2586 radiation survey meter. This model, introduced in 1957, had the unique feature of removable plug-in detector chambers, which could be interchanged between high range and low range modules, and even operated remotely via a cable up to 100' in length, allowing emergency response personnel to safely take measurements while staying at a distance from high radiation exposure areas.
