This is a Low Profile Adapter (LPA) Steel Plan-B Suppressor Adapter, model 859-859-308 B. It is in as new condition. The bag it came in is labeled “6.5 A R Suppressor Adapter “. The bore is 0.356 and 0.859. Another one is marked #7401754 25B, used and without the thread protector. I will ship for postage costs. $ 40-10%=$36.00 each. Please see my other ads. Thanks, Joe.