Signal repeaters were devices created by Bentley to assist Sly Cooper in his quest to reclaim the Thievius Raccoonus from the Fiendish Five. He set them up throughout the various locations that the Cooper Gang traveled to in Sly Cooper and the Thievius Raccoonus. They were first introduced in Raleigh's hideout in the Isle of Wrath, during the mission "A Stealthy Approach."
Signal repeaters served as checkpoints; should Sly suffer a fatal injury, he would re-spawn from the last signal repeater he activated, due to the device "repeating" the path he had already taken. Their design consisted of a device with a camera on it. Whenever Sly got near one, the device would activate, and the camera would snap a picture of him. At the same time, a holographic image of the Cooper insignia would appear above the device, which indicated that the signal repeater had already been activated.