Here you will find gas gun specific upgrades like nozzle parts or valving, and external parts that are more specifically for the externally more realistic guns, such as gas guns.
(ex. gas guns use standard thread pitch on their upper receivers while aeg's tend to use metric thread pitch) (ex. 2 gas guns tend to use true milspec, we for example, or commercial, some WA platform guns, dimension buffer tubes while aeg's may use various non-standard sizes)
RE: External parts found here and usage on AEG's
There are some exceptions to the "realistic external dimension" rules, like Systema and Celcius for example. A few AEG manufacturers go to great lengths to ensure very "true" dimensions, but buy these parts for your AEG at your own risk. At best it may be a loose fit, at worst, it won't fit at all.
All Airsoft guns sold are shipped with a permanently affixed blaze orange tip in accordance with federal law.