Faxon Firearms Plan B Barrel Adapter Stainless Steel Black. The Faxon Titanium Plan B ? Hub Adapter (FF-MD-SIL-HUB-PB-02) uses Grade-5 Titanium (Ti-6Al-4V) to provide a strong repeatable interface from MuzzLok Plan B and similar Plan B muzzle devices to hub-mount suppressors such as Faxon HARMONIX and CORESYNC. Specifications for Faxon Firearms Plan B Barrel Adapter: Manufacturer: Faxon Firearms Finish: Stainless Steel Fabric/Material: Stainless Steel Features of Faxon Firearms Plan B Barrel Adapter Adapter Type: Plan B Hub Mount Adapter (Standard Plan B Hub Mount) Material: Grade-5 Titanium (Ti-6Al-4V) Precision Threads: 1.375-24 UNS-2A (Plan B side) & 29/32-24 UNEF-2B (hub interface) Finish: Natural titanium passivated Compatibility: Interfaces Plan B muzzle devices to hub-mount suppressor hubs (HARMONIX & CORESYNC) Package Contents: Faxon Firearms Plan B Barrel Adapter Faxon Firearms FF-MD-SIL-HUB-PB-01: Plan B Barrel Adapter Stainless Steel Black