A Scouter is a fictional device from Dragonball Z. Its primary function is to seek and calculate a organism's Power Level or Ki. It is small computer that is worn over the ear with a monocle that covers the left eye. The monocle provides a visual interface for the computer, which can be be manipulated by the means of a small button on the ear-piece. They can also be used for communication and relaying data across incredible distances. The older models have a tendency to explode when reading higher power levels.
See the Official Power Levels list for all known power readings throughout Dragon Ball Z.
As revealed in an Anime Filler episode, King Kai reveals where the Saiyans and Frieza obtained their advanced technology. He tells Goku that the Saiyans were not the only race who originally inhabited Planet Vegeta, there was also a race called the Tuffles. The Tuffles already had a highly advanced civilization, while the Saiyans were still a primitive race, living in caves and wearing loincloths. The Tuffles had nothing to fear from the Saiyans until a Saiyan who would later be called King Vegeta, united the tribes and started a war between the two races. The war continued for many years until the Saiyans saw their first full moon, which happens once a century on Planet Vegeta. The full moon caused the Saiyans to transform into Oozaru, which allowed them to easily wipe the Tuffles out and destroy most of their cities. After the genocide of the Tuffles, the Saiyans took the technology that interested them like their armor, and the invaluable Scouter.
Manga readers are left to assume that the Scouter technology was developed by Frieza's scientists and eventually issued to the Saiyans like the rest of the aliens under his employ.
 List of Characters Who Have Worn Scouters
- Captain Ginyu
 Appearances in Other Media
The Scouter device has appeared in many Dragon Ball video games, toys and of course the original DBZ manga volumes.