Part of the standard issue US Molle II system: this holds the standard entrenching tool, aka shovel.

These are in ACU/UCP (that grey digital camo that blends in with a gravel pit and grandma's couch) 

We also sell the shovels, though they are sold separately. 

NSN: 8465-01-524-8407

These feature a flap closure with plastic buckle, and two molle straps on the back. 

These will be from a variety of makers, but all are genuine US Government issue and in excellent shape.