Awesome magazines for the mp9. I bought two when I purchased my mp9 and they both perform great except for one little issue with the fill valve o ring on one mag. when filling it with gas, I accidentally tilted the green gas canister back and it sent the o ring for the fill valve across the table and i lost it. other than that they're great! replaced the o rings with mad dog red o rings and they are perfection in a magazine.
Holds a ton of gas enough for 80 shots but only 50 rounds
Metal feed lip
Heavy(just as heavy maybe heavier than the mp9 it self)
Can shoot 80 shots filled with gas, but only holds a max of 50(not an issue with me though)