A locator, also known as a location beacon, was a personal device that functioned similar to a homing beacon, sending a signal that allowed the device to be tracked. A number of the Grand Army of the Republic's clone troopers, such as Clone Captain Rex and trooper Tup, carried locators as part of their battlefield equipment.
Some types of datapads came with a built-in locator device. There were also military-grade locators that were capable of broadcasting a signal through just about anything, short of a few metric tons of lead or an Imperial jamming field.