The Metal Detector is an optional gadget in Ratchet & Clank. It allows the user to detect bolts hidden under ground, by pointing the user to them and then sucking them up through the device to obtain them.
The Plumber gave the device, originally created by his grandfather, to Ratchet on Batalia after the mission "Destroy the bombers". While not developed by Gadgetron Corporation, they had extensive records on its use.
The Metal Detector displays red or white beams when is held down, which show the user how close they are to the bolts. White beams aim at the floor when there are none nearby, though when some are near, a bolt indicator will appear on the screen and using the Metal Detector will cause the device's beams to point towards the bolts and for the beams to become louder and make a higher pitch sound. The beams become more intense until the player reaches the bolts, with the intensity of the beam indicating the proximity to the bolts.