SB Tactical SBT Brace Fixed Right Side Folding Black Synthetic for H&K UMP, B&T APC, LWRCi SMG45 The SBT-G2 Pistol Stabilizing Brace is the second generation of the SBT and enhances your B&T APC, HK UMP, or LWRCi SMG45 with an integral, right side-folding mechanism and an arm cuff based on the SB-Mini. The SBT-G2 provides you with all of the advantages of a pistol with improved control by adding an additional point of contact for stabilization.