Homing beacon given to Stargate Command and Atlantis personnel, allowing them to be beamed out of unfriendly territory by the Asgard transporters installed on Earth's battle cruisers. KEY EPISODE(S) - Off the Grid - SG-1 is the first unit to be given locator chip implants. The Scourge - Because of the planet's unusual magnetic activity, SG-1 is unable to be detected on the surface of Gamma Site by the Odyssey.  |