If you have a folder read below... - ODIN Works 9mm Adjustable Buffer

I use this Odinworks adjustable buffer on an ar9 PCC I've been building.. if you're familiar with ar9 BCGs then you'll know some of them have a weight pinned in at the rear of the bolt.. and if you want to put a folding adapter (i used the law tactical) then you'll need to un-pin that weight, therefore losing some of the reciprocating mass.. Other reviews have mentioned the 23 grams minimum total weight for BCG and Buffer, I'm here to mention this WILL help get back to that magic number if you have to remove the Bolt weight for a Law Tactical folder. My PCC now cycles and feeds reliably AND has a good cyclic rate for those times you may want to be super safe about things ...

I also recommend a little thread lock for all the set screws (once you have your preferred weight adjustments tuned in)