Viridian Reactor 5 Red Laser Sight for Smith & Wesson M&P Shield featuring ECRThe Viridian REACTOR R5 R Gen 2 red laser sighting system for the M&P Shield. This laser sight is easy to install and blends seamlessly into the trigger guard for invisible profile and smooth draw. Viridians red lasers utilize a 635 650nm laser wavelength to generate the brightest, sharpest red dot possible. These lasers feature 2 modes of operation (constant and strobe) and up to 12 hours battery life. The new gen 2 models feature a new INSTANT ON