Fits most sizes does not do 6.5 cm or 40cal

Met expectations.

These bore sight lasers make zeroing a rifle or hand gun simple and easy. I used these to pre-zero my rifle. Once I got a rough zero, off to the range and zeroed in 3 shots 2 minor adjustments. I would definitely recommend this product.

Helped get it on paper. Batteries. Do not last long

Easy to use. Love the different sizes.

The lasers are bright and it’s great to have all the different calibers. There are no shortage of batteries as well.

So, here's the deal, setting up a scope or red dot on your rifle or pistol can be a real pain and I can easily waste half a day and a bunch of ammo (and ammo nowadays is not cheap!). Why? Because of the recoil! If you don't hold your firearm properly or firmly enough, the point of impact changes from shot to shot due to the recoil, and it cannot be used reliably for your sight adjustments. This is especially true for pistols when you are shooting off-hands. And for rifles, even if you are using a bench rest or a bipod, it's much harder to properly sight your rifle at 50 yards (or even 100 or 200 yards if you are going for long range shooting) as the slightest movement affects the point of impact greatly. Plus, don’t forget about higher rifle power to cause higher recoil. Here comes a bore sight laser to the rescue! This kit comes with everything you need to make your life easier - 7 most common calibers (.223REM, 9mm, 7.62X39mm, .30-30WIN, 30-06, 308WIN, 45ACP) all neatly packaged in a rugged plastic case! This kit seriously saves me tons of time and ammo. It projects the exact impact point of your shot and zeroing of your scope is super easy - just align your scope’s reticle center with the projected red dot, and you are good to go :). Of course, you’ll have to do follow up adjustments after that for holdover and windage, but you save a lot by skipping initial zeroing to the “absolute” point of impact.The cartridges seem to be very well-made, they are all brass, so it shouldn't damage your chamber when you load and unload them. The cartridges fit perfectly into corresponding chambers and eject easily. The red laser is very bright and easy to see even on sunny days outdoors. Said that, I would really prefer it if they would use green lasers instead, like I have on my other sighting tools. You can correct the projected laser point if it's off with a few small screws, but I found that all cartridges were zeroed out of the box, which is great! To verify that cartridges are properly zeroed, I did the "rotation test" and rotated the cartridge while it's chambered and my rifle is in a fixed position on a bench. The projected red dot did not change its position, which means it's 100% on spot. By the way, there is no "on/off" switch on these cartridges. When you insert batteries and screw the back end, it turns on immediately and will remain on until you remove the batteries. Not very convenient, but I guess there was no space for an on/off switch due to the small size of cartridges. As an added bonus, they include 24 spare LR41 batteries, so it will keep you going for a while.Bottom line:Setting up a scope or red dot can waste time and ammo due to recoil, affecting accuracy. This CVLIFE laser bore sighting tool kit, compatible with 7 common calibers, makes sighting easier by projecting the shot's impact point, allowing for quick scope alignment. The well-made brass cartridges fit perfectly and eject easily, with a bright red laser visible even outdoors. While it lacks an on/off switch, it includes 24 spare batteries, making it a time-saving solution for zeroing your firearm. They come pre-zeroed out of the box and include a sturdy case with a bunch of extra batteries. Overall, it's efficient and effective and well worth its price. Highly recommended, 5 stars in my book!Pros:1. Bright red laser, visible outdoors.2. Includes 7 most common calibers.3. High quality, all brass construction.4. Fits perfectly in the corresponding chambers.5. Pre-zeroed and ready to use out of the box.6. Comes with a sturdy protective case.7. 24 extra batteries included.Cons:1. No way to turn it on and off.2. Red laser is not as visible as green.

Very easy to use and simplifies the sighting-in process for scopes.