I think I got it in a large lot that I purchased, thinking it was an Uzi mag.
I have not put it in a Tec 9, but I have examined it against picturse of a Tec 9 and the fittings do not appear to be the same.
2A: "A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed." US Army Combat Veteran and Paratrooper: OIF (2008, 2009, 2010) and OND (2011). Bronze Star Medal and Meritorious Service Medal recipient. SAF and NRA Lifetime Member. I'm a lawyer, but not YOUR lawyer and I have not offered you legal advice.