This is one of the gadgets of soldiers with modern loadouts. This is one of the complement that everybody will copy soon: the Blast Gauge System.
WHAT IS A BLAST GAUGE SYSTEM?
The real model is a triple detector adapted to the helmet, the vest, the shoulder… It measures the pressure and the acceleration of an explosion. It recuperates all the needed information for the medical team to possess everything.
Obviously, like everything new, interesting and military, above all if they are Special Forces; this model is replicated in airsoft. You can already find a replica (a dummy) to complete your load outs.