PA-60 Ammo can/box
U.S. Military use to protect, store and shipping 60 mm ammo, it has a clamp-on lid, same design as 30 cal. and 50 cal. ammo can, even in sizing,
the PA-60 and M2A1 almost have same size of lid, since World War II，along with many other types ammunition contianers, PA-60 has been used in decades already.
In a lot of retail stores in U.S, people can buy a brand new ammo can, like M2A1, M19A1, with a gasket in the lid, it can resist moisture for storing a lot 
of thing, coins, old envelope.
Yunkai Start producing PA-60 since 2017. Capacity of this ammo box is 1,200 pieces every day, all the cans are airtight tested.