The G&G STP-45 pistol, available at Camphoenix Arena & Shop features a CNC-machined metal trolley and castle cart, reinforced with a durable Cerakote finish. This is equipped with the patented PAI (Precision Accuracy Innovation) System, a hop-up adjustment mechanism that allows for incredibly fine-tuned control with 39 possible settings, each moving the hop-up by just 0.019mm for a total travel of 0.74mm.