Gentlemen, recently found 2 Japanese type 90 helmets and 4 covers in the locker of WW2 Supply Sergeant. His military career spanned WW2 through at least 71/72. Helmets appear to be in unissued condition scarred only from stacking. Helmet shells are identical. Liners and chin straps are different. How many manufacturers of helmets did the Japanese have? Covers also apppear unissued with only some rust marks around edge and wear to outer edge that would suggest they were on helmets at one time or another. For some reason pictures did not load in the correct order. Your opinions would be greatly appreciated.