I've always been a naysayer when it comes to hi-caps, but these magazines made me think otherwise.
Realism arguments (and the fun of reloading frequently) aside, these hi-caps remove what was, in my opinion, the biggest problem with hi-caps: the winding wheel on the bottom.
Wheels look stupid, take forever to wind (and you have to do it constantly), and are painful to wind if you're bare-handed or it's cold out.
These mags remove that problem by using a really cool pullstring (which i believe is made of a metal wire) to wind the wheel for you. the wheel is also concealed under a flap that's easy to open, but doesn't just pop open if you shake the gun.
Basically, they look like mid-caps and have no painful and time-consuming wheel, but they have the epic capacity of a hi-cap. the only place you lose is that they still make noise as the loose bbs move around inside..
Overall, these are amazing magazines: beautiful build quality (metal), they feed excellently, and they make winding your hi-cap fast and painless, which is a HUGE advantage in cqb and saves your fingers in long, potentially chilly (i live in michigan) field games.
THESE ARE A MUST-BUY for anyone who uses midcaps. I cannot express how happy I am with these magazines.
-metal construction with quality paintjob (it's a pretty dark tan)
-no unrealistic wheel visible on bottom
-pull-string winding is faster and less painful than wheel winding.
-bbs make that tacky jostling sound because it's a hi-cap
-hi-caps are inherently unrealistic :\