Can any one take a look at the black box in front of his aimpoint and tell me what that is?

Link:
https://gko.ngb.army.mil/Login/Images/IMG0107.jpg



Some one i asked thought it may have been miles gear (Armys laser tag training equipment)

but the excerpt under it :
"Staff Sgt. Charles Houck and Spc. Tom Blalock, from the 98th Cavalry Regiment, 155th Brigade Combat Team, search for insurgents near Al Tunis, Iraq, after their fellow Soldiers and Marines were attacked. This photo appeared on www.army.mil."