At the heart of all Top Tech rifles is a brand new version 2 gearbox which uses a completely new blowback system powered by air rather than being driven off the piston. While this makes it a little more subtle in operation, it adds a whole lot to the experience in terms of sound. The ejection port cover flies open on the first shot and there is a definite mechanical rattle (of a very good type) as the gun fires. Our testing would also suggest that these patented gearboxes are a whole lot more refined than the G&Gs of old, sounding and feeling very smooth and taut. Perfomance is first rate too, with approx 330 fps at the muzzle and exceedingly consistent grouping at 15 metres. Build quality is everything it ever was - top quality and solid as a solid thing celebrating Solid Day! A brand new hop unit is added too, showing no signs of the dreaded 'creep'. Interestingly this new unit is plastic, perhaps signifying what some of us have suspected for a long time, that more flexible plastic makes for a better air seal. The M4 Lite (their description..!) is basically an M933 Commando, ideal if small guns or CQB is your thing. Internally it is identical to its bigger siblings and is no less solid. It certainly looks like G&G have really done their homework - if that indeed is the case, other manufacturers had better look to their laurels! Comes beautifully packaged with a G&G 450 round hi cap magazine, manual, cleaning rod & wrench to tighten the barrel/receiver joint & to remove the flash hider. Nice touch!