Really good AA batarang locking mechanism!

I just logged into YouTube and saw this really good Arkham Asylum / Arkham City / Arkham Knight locking batarang video!  I’m not sure who this guy is, but he’s made a really cool batarang.  It looks like the batarang is cast in fiberglass, and he’s obviously cleaned it up well and added the custom parts needed to make a really good AA batarang locking mechanism.  

I actually tried this in the past with a crude sculpt, using magnets to lock it in place, but never spent any more time on it.  The version in the below video is just AWESOME.  Check it out: