Part of the standard issue US Molle II system: 9mm Magazine pouch (single). Aka, the pistol magazine pouch.
These are in OCP/Multicam
NSN: 8465-01-580-2610
These feature a single flap with metal snap, and will hold a 9mm pistol magazine. They are will work with most pistol magazines as long as they are about 15/17 rounds in capacity. Would also fit most smaller sized flashlights.
These will be from a variety of makers, but all are genuine US Government issue and in excellent shape.