Ultra bright 635nm laser provides superior accuracy for all firearms. Site-Lite SL-150 Ultra Mag Laser Boresighter fits all calibers from .22 to .50, plus 20 ga. and 12 ga. shotguns. No metal contacts the rifling, and no optional arbors are required. Includes scope alignment verification system target to verify scope alignment in the field. Super-strength rare earth magnets hold it securely in place. Includes rugged carrying case and super-long-life CR2 lithium battery for over 40 hours of continuous use.