Floatation bladder, US military surplus

This is a US military surplus flotation bladder.
I purchased it about 30 years ago. Although it's unused, there are some stains and dirt due to long-term storage. I inflated it with an air pump and checked it by hand; there are no leaks, but since it's old, I think it's best not to use it for practical purposes.

Detailed Information (Google AI Response)
Product Name: FLOTATION BLADDER MK I MOD 0
Manufacturer: PAN AVION
Contract Number: DSA100-67-C-0410 (This number indicates that the manufacturing year was the 1967 fiscal year)
Part Number: BUORD DR 982514
Manufacturing Date: DEC 2 1966
Purpose: When fully inflated, it provides 110 pounds (approx. 50kg) of buoyancy for humans and 12 pounds (approx. 5.4kg) for average cargo. This is a flotation bladder adopted by the US military during the Vietnam War era.