I have a A3 folding stock with the picatinny adapter. It does have the stormwerkz buttplate adapter. If you need a brace, you can take that off and put a gearhead works style buttplate.
Its about 10" overall length. I had this on my SBR stribog but went with a different stock.
$180 obo
210 two 8 9 two 569
Open to trades