It still has a separate removable inner protective sleeve,....marked COVER M403
and two internal / built in sleeves
It looks unissued - near mint condition
these were used to carry the complex slide rules and other various tools the WW2 artillery officer would have used to plot and correct artillery fire from the big cannons
As nice as you will find one
Don't pass it up
Real WWII USGI WW2
United States military issue