Flash Optics&trade; Red Laser Bore Sighter .177 .22 .25 .308 .357 .40 .55 .65 Caliber Fit Rifle Pistol Handgun Quickly sighter in any rifle or pistol .177 .22 .25 .308 .357 .40 .55 .65 caliber. The laser bore tool is precision CNC machined from aircraft aluminum. The laser bore tool is hardened with a very durable finish to maintain the precision surfaces. Each unit is calibrated at the factory, utilizing high precision alignment tooling. Length is 6 inches and .625 diameter at head , weighing only 1.2 ounces.