what is the square on the back of rugby shirts

The square on the back of rugby shirts is a visible part of a sophisticated biometric tracking system used by coaches to track a variety of metrics such as distance and speed. This system is composed of a GPS tracking device that sits between the shoulder blades in a fitted vest. The GPS pod is designed to sustain collisions and is inserted into a sleeve in the back of the rugby jersey. This system is used to measure and analyze the performance of the players. The rectangular lumps inside players shirts, between their shoulders, are the GPS pods that are used to track the players' movements. The GPS system is used to give rugby teams an edge by providing coaches with data on the players' performance, which can be used to improve their training and performance on the field.