The Tag Rounds are specialized, non-lethal ammunition created by Leo Fitz in order to track a target shot with the round. Each round has an attached micro-receiver that is implanted on contact, allowing S.H.I.E.L.D. to track the target via satellite.
Agent Leo Fitz designed the Tag Rounds in order to help S.H.I.E.L.D. on one of the most important missions tasked to his team, investigating former candidates to the Index in order to verify if one of them was the real identity of the Clairvoyant.
Felix Blake took a magazine charged with the Tag Rounds to Tranquility Bridge, an assisted living home in Macon, Georgia, where he would have to investigate Thomas Nash with fellow agent Melinda May. However they came across Deathlok, shooting him and finding that conventional bullets were useless against him. Blake changed to the Tag Rounds and fired, hitting Deathlok with the bullet and successfully implanting a micro-receiver.
After taking a critically injured Blake to the Hub, Phil Coulson realized that Blake had planted the Tag Round on Deathlok, and ordered Skye to access S.H.I.E.L.D. Satellites to track him, leading the team to an abandoned race track in Pensacola, Florida.
- Fitz-Simmons Armory Link