The interior of the helmet seem to good condition seems to be mostly intact from what I can tell. (please see detailed pic for actual condition).
Rubber liner does have some tears. Some of the wires are severed as pictured. I'm not and expert and have limited knowledge of this helmet. K-1 Helmet:The K-1 high altitude partial pressure helmet made by International Latex Corporation was the first U. High altitude helmet in the early 50s. It was composed of an inner hood/neck skirt with rigid metal frame and a one piece green fiberglass outer shell connected to the rigid metal frame of the hood. The removable face plate was made of molded plexiglas for light weight, improved visibility and cost reduction. It was electrical heated by way of tiny wires moded within and used a low pressure oxygen system. The K-1 was later used with the MA-2 face plate with the high pressure oxygen system. This item is in the category "Collectibles\Militaria\1954-60\Original Period Items".The seller is "grandantiques" and is located in this country: US. This item can be shipped worldwide.