Red laser boresighter kit. This kit will fit any calibrle firearm with these 12 arbors for a better fit in more calibers, and a more convenient "push button" on off switch. Universal Laser Bore Sight kit includes arbors for .17 (.177 airgun too) all the way through to .78 caliber (12g) Boresighters are ideal for helping you to get on paper before spending expensive rounds zeroing in your scope or iron sights at the range. Comes in a storage box with foam padding. CR2 battery included but not warrantied For handguns, rifles, shotguns. 1) .17 to.177 2) .22 to .25 3) .264 to .284 4) .30 to .32 5) .338 to .358 6) .375 to .410 7) .416 to .45 8) .458 to .460 9) .500 to .540 10) .535 to .61 11) .57 to .64 (20g) 12) .69 to .78 (12g) Easy to use, instructions included. Spend less time and money on expensive rounds sighting in and more time in the field! (if you have a 17hmr this may not fit if barrel diameter is less than 4.5mm). Top Tip; For more accuracy, the windage and elevation on this boresighter can be adjusted using a gun that’s already sighted in to get it that much closer to the bullseye. Try it at 8-10m inside the house using a bipod for example. Then its mainly a case of scope elevation when completing the sighting in process at the range.