One of the best bren2 adapters - Arms Republic Picatinny Stock/Brace Adaptors

The Bren2 version is excellent. Its nearly a carbon copy of the OEM rear except its a pic rail. You transfer the oem pin, locking lever and hardware over from the stock buffer tube mount.
Pairs really well with Haga pic stocks if you want complete transferability and standardoze on pic adapters VS. the B&T/SB tac, G36, ACR or any other type. It simply gives you more options versus having to buy a specific bren2 adapter for each type. Some are 3d printed nylon (i dont like the fit, look or durability of FDM nylon), some are 6061, etc. Just allows you to have 1 adapter for all guns (pic rail) and gives you a ton of flexibility for the dozens of stocks out there.

I wouldnt buy any of the nylon versions over this. For the money, this is the best Bren2 pic rail adapter hands down.