I'm clearing out the previous generation of NEA 556/223 muzzle brakes. They are 1/2-28 thread and are reduced to $7.95. While supplies last.
http://www.theammosource.com/index.php?main_page=product_info&cPath=14_288_289&products_id=6724
http://www.theammosource.com/index.php?main_page=product_info&cPath=14_288_289&products_id=6724