Evike had a "Daily Door Buster Deal" on the "Matrix Mil-Sim Metal M4 / M16 130rd No Winding Mid-cap Magazine". So we ordered two of them. When they arrived, they were packed like the photo below.
Nothing on the packaging says "Matrix". Instead, it's branded "Asia Electronic Guns". The magazine is metal, no winding, mid-cap, and fits the M4/M16 airsoft rifle. The finish is matte black, which reflects very little light.
The top of the magazine is the typical feeder and a switch to unload all BB's at once. The switch actuates easily with fingernail. To load these type of mid-cap magazines, you'll need a speed-loader. The benefit is that the magazine won't rattle with loaded BB's.
Many people's comments on this product said they got the same thing and it only holds 68 rounds. I was able to load about 80 rounds, far short of the 130 round claimed on the Evike product page. And it is rather long for a magazine that can only load 80 rounds. If you are planning to play MilSim and only load 20, 30, or 40 BB's per magazine, then this magazine is just fine.
A hex screw on the bottom of the magazine allows you to take it apart. You'll need a 2mm hex wrench. A precision Torx screwdriver also works. The T9 Torx bit fits perfectly in the hex screw.
Once you unscrew the hex screw, you can pull out the plastic insert (see photo below), from the top, which contains the actual feeding mechanism. Seven screws keeps the insert together.
If you unscrew all of the screws, you can take the entire magazine apart. See photo below. There are two springs combined into one. This magazine has a 70 rounds limit. We wonder if you can make it a higher capacity magazine by removing one of the springs.
To reassembly, assemble everything except for the last screw that holds the top in place (see photo below). Then feed the springs into the magazine. Once the spring is fed into the magazine, close the top and screw it in.
Note that if you just want to clear a jam, you don't have to take the whole magazine apart. Just remove the one screw and open the top.