This design saw service for a long time, starting in the 60's. A tough, well made piece, great for all those fiddly little things you need to carry with you in everyday situations.
Unfortunately these are only the bags, no mask included. Still, it is better than nothing! This is the Vietnam war model, but it saw service well into the 90's, and probably beyond.
The bag is made of thick OD canvas with reinforcing on the sides. The straps are nylon or cotton with metal hooks. Standard Lift the Dot closure. In Vietnam most soldiers couldn't be arsed to carry the mask itself, but the bag proved useful for carrying miscellaneous items.
Used but perfectly serviceable.