India, July 17 -- Ahead of the 2026 FIFA World Cup final between Spain and Argentina on July 20, there's reignited interest around a piece of technology football fans have seen before: the tight, cropped vest worn by players under their jerseys. Often mistaken for a sports bra by internet users, it is actually a GPS tracker vest designed to monitor performance.

The vest contains a small GPS device placed between the shoulder blades that records data such as distance covered, sprint speed, acceleration, workload and movement patterns during matches and training. The data is then used to customise workouts, monitor fatigue and reduce injury risks.

The crop-top design is purely functional - it keeps the device in place as players sprint on...