The NATO HUB is fully compatible with all 1.375x24TPI "HUB" compatible suppressors on the market today and is constructed of stainless-steel components. This HUB is compatible with all NATO-Spec A2 flash hiders and features a unique gate lock and ratchet system for redundant reliability and rock-solid fitment. The same suppressor attachment system is relied upon by NATO forces worldwide. The HUB version is simply threaded into compatible suppressors and snugged up with a spanner wrench. HUB assemblies can be semi-permanently attached using Rocksett or other thread locking compounds should the end user desire. Fully HUB Compatible (1.375x24TPI) Constructed of Stainless Steel NATO-Spec A2 Compatible Attachment Interface Relied Upon by NATO Forces Worldwide 5.56x45mm & 7.62x51mm Compatible*This is a HUB Accessory Device Only this product is not a suppressor & a suppressor is not included.