Introducing the A2X Flash Suppressor. (by BCM®) The A2X is an extended version of the A2 flash hider found on the M16 and M4 series of rifles. Threaded for your 5.56mm carbine. Machined from 4150 steel. Phosphate coated per MIL-STD-171. Predrilled hole at the base for permanent installation. When mounted per BATF specifications for a permanent installation it will bring your 14.5" M4 barrel to a non-NFA length of over 16.1". Installation should be done by a qualified gunsmith familiar with BATFE regulations. The A2X is predrilled and comes with a dowel pin and crush washer for installation.