Retro Arms CZ Billet CNC 8mm Ver.2 Gearbox Shell for VFC Quick Change Spring Series Airsoft AEG Rifles

"Been intending to review these gearboxes for a while, here goes...Simply put, best gearboxes I've ever used. I know it's hard to spend over a hundred bucks for just a gearbox shell, but it's kinda like buying a nice car and putting really bad Mexican gas in it (no offense to my brothers but that's some bad gas). The Retro Arms gearbox is not just extremely well machined to perfect specs and tolerances, it's unbelievably lightweight. You can start that important build with a solid and dependable foundation, knowing that almost every after-market, high quality upgrade part you put in these GB's will fit perfectly with no mods needed, and that these are as close to unbreakable as you can get. (I say 'almost every' because there's always those cheap, out-of-spec parts). There are also a couple small innovations that Retro Arms incorporated into their GB design: a window to release the anti-reversal latch, a small window to observe proper AOE alignment, better studs to hold the trigger switch and tappet plate springs, better threaded holes with accompanying screws to hold in the trigger switch and cut-off lever, quick change spring feature, oversized grooves to allow wiring to run a variety of pathways for different builds, and different models depending on what gun with special features you may be using. All of this and the precision of the CNC work will make you wonder why you would ever use anything else. Expensive? Not really. Bad parts that lead to GB failures are expensive. Avoid that part and start with one of these.