The Bore Sighter Kit from BSA Optics is a 15-piece kit designed to assist in aligning weapon optics. The kit includes a wide range of metal arbors to fit the majority of firearm calibers. Helps save time and ammunition by allowing you to precisely align optics before hitting the range. Comes with .177 Arbor .22 Arbor 6mm Arbor .25 Arbor 6.5 mm Arbor .27 Arbor 7 mm Arbor 30 Arbor .32 Arbor .338 Arbor .35 Arbor .375 Arbor .44 Arbor .45 Arbor .50 Arbor. Product Features 15 piece kit Align optics before hitting the range Includes arbors for popular calibers Case included