Reviews Description: The SL-100 uses a red laser and has approximately 2 hours continous battery life. It's guaranteed more accurate than any other boresighter. That's why the US Navy and USMC selected our boresighters, over all others, for their Aviation Unit weapons from 5.56mm to the 20mm canon on the AH-1Z Cobra Attack Helicopter. In addition, the US Navy is using our boresighter, with our special adapter, for the 25mm Gatling Gun on the new F-35 Strike Fighter. The SL-100 includes all adapters to fit .22 cal. To .50 Cal. & 20 and 12 ga. shotguns. The system also includes our Ballistic Targeting System software program to create a custom laser boresighting target for your specific rifle and ammo. All Sitelite Mag Laser Boresighters have a lifetime warranty. And, an optional app is available for your iPad and iPhone for use in the field.