This laser is perfect for my husbands pistol, very impressed with the quality, the laser and how easy it was to install on his pistol.  This comes with the batteries, and the allen wrenches for installation.  You get a nice instructional sheet, but it was so easy you really did not need, since we know how to install.  The laser itself is nice and bright and it is perfectly straight, good lining up with target.  If you needing a good laser I would be very happy to recommed this to family, and friends.  I personally found not problems or issues with this laser.  Did a little practicing too.

http://www.amazon.com/Feyachi-Tactical-Laser-Pistol-Picatinny/dp/B01BTKMH78/ref=sr_1_1?ie=UTF8&keywords=Red+laser+dot+sight