This is a Crimson Trace Corporation LaserGrip known as the Master Series, model LG-904G.
Machined to fit seamlessly while bringing both artistry and rugged engineering to John Browning's classic 1911 design" Green Master Series(TM) Lasergrips(R) are sure to impress. Featuring ergonomic and aggressively durable G10 side panels with a rubber overmolded activation button; these are the ultimate laser sights. Standard to Crimson Trace Lasergrips" the LG-904G features Instinctive Activation(TM). This means that the laser sight automatically springs to life when the weapon is held in a natural firing grip.
Features:
Pressure activation
Green laser
Factory sighted at 50Ft
.5 inch diameter at 50 feet