Glock PG3150201: The Glock 31 Gen4, in .357, introduces revolutionary design changes to the pistol that has been the optimum solution for those seeking high muzzle velocity and superior precision in a reliable, yet lightweight, pistol with large magazine capacity. The modular backstrap design lets the user adapt the grip to hand size, and the frame surface exhibits the scientifically-designed Gen 4 rough textured technology. This model features a dual-recoil spring assembly that substantially increases the life of the system, and the enlarged reversible magazine catch easily accommodates left- or right-handed operators. The Generation 4 frame retains the Glock accessory rail for accessory attachment.