I purchased one of these because it was cheap, but only to try it out. I haev a custom M4 that has a rate of fire at 43bb's per second. Feed flawlessly. Honestly better than the lonex mags I have.
I have run 5000 rounds through this magazine without jamming or failure so far.
Keeps up with high rates of fire.
Sturdy pull cable
Fits King Arms magwell perfectly
Needs more than 5 pulls for a full mag (Honestly better than turning a wheel though)
String can get stuck halfway out (Needs full pull to retract)
Rating: [5 of 5 Stars!]