For sale is a Hera Side Folding Unit (SFU). It was used on a CZ Scorpion, and then a Sig MPX until my Form 1 was approved. No longer needed. $110 shipped to the US 50.
More info can be found here: https://www.lanworldinc.com/index.php/component/hikashop/product/334-hera-side-folding-unit?Itemid=9999
Pics: (NOTE: The SFU is the top item in these pics. The bottom item is a KAK MPX stock adaptor, not for sale here).