I have 4 of these mags for my G4 A3 Tactical Carbine, and they work like a charm. They feed to the very last BB and fit like a glove in the magwell. The plastic tab that everyone references is a little rod that shoots out about 3/4 of an inch and needs to be pushed back in or else it will break. Good mid caps for field and CQB, but not ideal for dropping and tossing around because of the ejected plastic nob.
-Feeds to the last BB
-Fits perfectly into G4 series magwell
-Longer than most M4 mags, makes it easy to pull out from mag pouches
-No misfeeding after several games of use
-79 rounds runs out fast, fairly low for a mid capacity mag
-Plastic nob can break, not ideal for fast paced reloading without a dump pouch
Rating: [4 of 5 Stars!]