Farpoint's Laser Collimator - 1.25/2" (650nm) is a precision-machined alignment tool. The 650nm, red laser diode is held in place by paired setscrews from four compass points, ensuring true alignment, even after repeated dropping. An aluminum ring protects the on/off switch, helping to prevent inadvertent power cycling. The laser is filtered by a .8mm aperture stop at the business end of the collimator. Rugged, yet smooth, this tool will provide years of trouble-free, accurate mirror alignments.