This is a real steel review with this brace to allow you one handed shooting with the SB15... "If you are like me, you remember seeing the Sig SB15 a while back and thinking 'hey they hacked the NFA'. Of course we all know how it is supposed to be used, but let us get real and look at this objectively: Sig made an “arm brace” and got ATF approval for said arm brace. The arm brace slides over a pistol buffer and looks like a stock… but it is an arm brace.