a number of other stacked blow backs, spyders, diablos, ect
spyder compact stock, diablo vertical stock, and the rhino stock.
Nothing really, possibly an expansion chamber, or a remote
inexpensive, performs like an expensive marker,
a little heavy, breaks cheap paint. out of production
Very good gun for the money, easy to strip and clean, pretty accurate with to stock barrel, very accurate, very reasonable rate of fire, dose not break good paint. The trigger is a little stiff but its a pretty short pull. There really isn't much more that can be said. the gun has been quite durable and reliable. I haven't had ant problems with it.
This is a very good gun for the money I would recommend this gun to anyone starting out. the only real down side to this gun is that it is out of production and its a little heavy, but a remote line will lighten the gun right up.