BOREVIEW My View Original .223 5.56 .30 or Larger Glass Mirror Views Entire Interior of Barrel to see Obstructions Cleanliness Quality High-grade glass mirror in all aluminum casing that fits into your barrel. Allows view of entire interior of barrel to see obstructions, cleanliness or quality. Fits into .30 caliber or larger barrels. Can be used with smaller calibers (ex. .223) by placing tool against face of chamber and aligning mirror with barrel. No Battery Needed Manufacturer's Lifetime Warranty Included.