MILITARY DOUBLE AMMO BOX/STORAGE TRAY
40 MM AND 50 CALIBER CAN HOLDER.
INSIDE DIMENSIONS ARE 6" x 11" AND 8" x 17.5"
P/N 12340176-2
NOS-NEW OLD STOCK 
NSN 2590-01-262-9515
WITH INCLUDED HEAVY NYLON WEBBING STRAPS(12340507-5) TO SECURE YOUR CANS.
U. S. Sales Only. 
I've included a picture with a can strapped onto the storage tray. The can is NOT included, I just wanted to show you how nicely it fits.