I have covered the TangoDown ARC magazine in detail previously but this is the first photo I have seen of the transparent model.
Click to expand. Photo ⓒ Chen “SMGLee” Lee. Used with permission.
The magazine utilizes a unique two part design. By using a stronger opaque polymer for the upper part they can make a magazine that is hardier than if it was fully transparent. The “glue” that binds the two parts together is apparently harder than the rest of the mag.
More about the ARC here.