The scouter (or scanner) is an instrument in the fictional Dragon Ball manga series, as well as the anime series of Dragon Ball/Z and its' anime equivalent also, which Freeza and his mercenary soldiers utilise to analyze a life form's power level. The Scouters were an invention of the Tsufurujin, who once occupied Planet Vegeta, along with the Saiyans, before they were wiped out. It's worn around one eye and can detect power levels from a few miles away.