The Large Thread Version Howie Glatter Laser Collimator - with a 650 nm laser diode beam. Fits your 1.25-inch barrel.
All of the Howie Glatter Laser Collimators are powered by a CR123A lithium cell, which allows for approximately 40 hours of operation. All Laser Collimators use a solid state laser diode that does not fade or change with time and use and are factory-aligned to 15 arc-seconds providing 0.1-inch accuracy at a distance of 20 feet. Shock resistant to keep its alignment - even when dropped.
With a choice of either 650 nanometer or 635 nm wavelength. The two lasers have the same power output, but the 635 nm laser appears about two or three times brighter due to the human eye's sensitivity to the shorter wavelengths. The 635 nm laser diodes enables holographic collimation in brighter ambient light and work best suited If you intend to collimate in early twilight. The 650 nm laser is better suited if you plan on collimating in the dark.