I/O Port seat back brace
http://www.ioportracing.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=SBB15
Bought it for a car I no longer own. Never removed from box, just opened to verify contents.
$85
good product!
might possibly need one for the second chumpcar we are building but I won’t know for a bit still.
Sorry, its sold.