We purchased the last of these from one of our suppliers, and don't have that many. Introduced in 1970, these served the Hungarian military for several decades, and when you get yours, you'll understand why.
Constructed of heavy duty aluminum, and designed to actually fit inside the mess kit if need be, these are a solid piece of field equipment. Holds about .75 liters (around a quart) of water, and is painted olive drab for concealment if attached to outside gear.
NOTE: These will all vary in color and condition as pictured. Some have dents, and some are slightly dirty on the inside, but all are in functional great shape and are ready to use. Some may have a belt clip on them, but most don't so expect to not get one. You can attach a carabiner to the ring that holds the cap on, and you're good to go.
I don't know if I'll be able to get any more of these, so grab one while you can!