The Viridian Reactor R5-R Gen 2 red laser sighting system for the Glock 17/19/22/23/25/26/27/28/32/33/35/36/38/39. This laser sight is easy to install and blends seamlessly into the trigger guard for invisible profile and smooth draw. Viridian's red lasers utilize a 635 to 650 nm laser wavelength to generate the brightest, sharpest red dot possible. These lasers feature 2 modes of operation (constant and strobe) and up to 12 hr battery life. The new gen 2 models feature a new instant-on ambidextrous, inside the waistband (IWB), custom fit holster with instant-on activation. Made of microfiber, this holster is more comfortable and durable than the previous models. The instant-on activation ignites the tactical light the moment you draw. No buttons, no squeezing, no doubt. When you draw, it's on.