In this review, ASG Olsztyn looks at the Maxx Model CNC aluminum M4E and M4G Standard M4 hop-up chambers that feature a BB latching system preventing BB loss when releasing the magazine and allowing easy removal by pressing a latch. This improved design minimizes misfeeding. Constructed with a solid aluminum adjustment wheel and a stronger spring for a tighter fit in the outer barrel, the hop-up chamber can be transformed into a tracer unit with an optional Maxx Model Dual LED board and module set.