20GA Brass Red Laser Boresight.  Caliber-matched brass bore sight exclusively for 20 gauge shotguns, crafted from premium solid brass for tight barrel fit. Equipped with a 635-655nm visible red laser under safe 5mW output, delivering clear aiming dot across 15–100 yards, with a 1.5-inch dot at 100 yards for simple optic alignment. 112g compact brass body inserts smoothly into shotgun barrels, enabling fast pre-zero calibration to save ammunition during hunting and range practice.