This is a genuine U.S. Military Issue compression sack, a component of the Military's Improved Modular Sleep System (IMSS). Made of a water resistant nylon fabric in urban grey / foliage color and cylindrical in shape. The stuff sack is equipped with a nylon drawstring for closure and hood style top cover for compression.
These compression stuff sacks were acquired from the US military bulk storage, and vary somewhat in condition, outlined below.
Bought a small compression sack listed as "very good" and it's pretty much brand new. Very pleased. These are great for carry 2 pieces of the IMSS or MSS.