The Viridian R5 Gen 2 green laser sighting system is easy to install and blends seamlessly into the trigger guard for invisible profile and smooth draw. Viridian's green lasers utilize a 510-532nm wavelength range creating an optimum target dot that is up to 50 times brighter than red lasers. The gen 2 models include 3X more battery life (up to 5 hours) and an INSTANT-ON ambidextrous, inside the waistband (IWB) holster with automatic laser activation. Made of microfiber, this holster is more comfortable and durable than the previous models. This model is compatible with Smith and Wesson M&P Shield 9/40.