L2D Combat 1/2x28 Barrel Thread Protector Bronze. The front and rear of the thread protector features a recess chamfer to accomodate and hide the included O-ring that is included with all of our L2D Match Grade Barrels. Specifications for L2D Combat 1/2x28 Barrel Thread Protector: Manufacturer: L2D Combat Threads per Inch: 1/2x28 Condition: New Features of L2D Combat 1/2x28 Barrel Thread Protector 1/2 X 28 9MM Threaded Barrels Package Contents: L2D Combat 1/2x28 Barrel Thread Protector L2D Combat 3HD-TDP-12X28TP: 1/2x28 Barrel Thread Protector Bronze