FIND IT HERE! https://doublemdefense.com/product/hbi-folding-brace-combo-for-stribog/ 

Factory New.

*** PLEASE NOTE: The current batch is made with the POLYMER HBI adapter. The function is the same; however, installation requires a rubber mallet applied with some force. ***

SKU: 10202-02

Comes With:
-HB Industries Folding Brace Adapter
-SB Tactical Brace

B&T APC9/MP5 type stock or arm brace adapter for your Grand Power Stribog SP9 A1/A2/A3. Our adapter is low profile and integrates the any B&T APC9/MP5 type stock or brace directly to the upper receiver of the Stribog. The assembly will maintain the side folding characteristics stock/brace. Our brace mount is machined from billet 6061T6 aluminum and hard coat anodized to MIL-A-8625, the SBT brace is polymer.

B&T APC9/MP5 Type Stock/Brace adapter for ALL Grand Power Stribogs
Side Folding with Seamless Integration into the SP9 Upper Receiver
Fits all Grand Power Stribog variants
Drop In, No Additional Parts or Hardware Needed
Machined Aluminum 6061-T6
Anodized MIL-A-8625 Type 3 Hard Coat
Designed and Manufactured completely in USA.

All NFA rules apply (if using this product on a pistol).

Gunsmith Installation Recommended for All Parts.