is it one of those kit guns, also where do they sell them? I like it.

That is a british STERLING. I've carried one on boardings as late as 2001 because of the "no chambered round" practice the officers put in place. The MP-5 carrying guys had to cycle thier weapons to make it good to go (fires from a closed bolt) The Stirling, basically a slightly more evolves STEN GUN replacement fires from an open bolt, so I was still while cocked following the rules the officers set down "no round chambered" yet I was ready to go while the MP5 guys weren't. The kits for these are a little more expencive and more involved to build that the sten mk.3 but anyone with mechanical aptitude can do it.