I've got something similar to Chef's version, also from eBay (although mine's Indian made rather than Chinese - I'm sure there's very little practical difference). A "Menbo CY-008" or something like that, I think.
One thing to be aware of is weight rating. Most of these 'cheap' arms seem to be rated for up to 12Kg or so ... and some of the very cheap ones are only rated to 4-5Kgs.
Purchasing my vest/arm some years ago, I didn't really have any idea of what a M56 might weigh as mine was years away from being completed (actually, it's probably still years away from
finished-finished

). Currently, my M56 is about 15Kg & that's without airsoft internals, I estimate it to be closer to 18 maybe 20Kg when I'm done so I may need to see if I can upgrade the arm at some point - the moral of this story? Research and askin questions before spendin coin = a real good idea!
