I've been all over the internet looking to identify this magazine. It came in a box lot at the last gun show. The rest were pretty typical S&W M&P, Beretta and Taurus but this one has me stumped.
It looks to be 9mm, holds 12 rounds and has absolutely no markings whatsoever.
Jimenez Arms JA-9. Not to be confused with the Bryco model 59, which is similar. Bryco 59 has a flat floor plate and no hole. Bryco 59 mags can be modified to fit JA-9 if you bend the floor plate and drill the hole.