This is a Viridian Weapon Technologies Laser known as the Gen 2, model 920-0005.
The Viridian R5 Gen 2 green laser sighting system. This laser sight 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. It features two modes of operation: constant and strobe. New features of the gen 2 models include 3X more battery life (up to 5 hours) and an ambidextrous" inside the waistband (IWB) holster with INSTANT-ON automatic laser activation. Made of microfiber" this holster is more comfortable and durable than the previous models. The INSTANT-ON activation ignites the laser the moment you draw. No buttons" no squeezing" no doubt. When you draw" it's on.
Features:
Adjustable windage and elevation
Green laser
Mounts to trigger guard
High strength polymer construction