Longer battery life for your bore sighting needs. The external battery box extends your battery life to 28 hours. The battery box doubles as a storage container for the bore site. Integrated Magnet lets you stick the battery box to you rfirearms while you sight in. Comes with a compact high quality nylon pouch to store and transport all of your boresights and arbors. Bore sight made from 100% brass for the highest quality and durability possible. .223 20X model available for long range shooters.