M23 Blank Firing Adapter (BFA), Yellow, NSN 1005-01-361-8208, for M4 / M4A1 (16-inch or similar barrel length).
Fits over the muzzle, fastens securely, and captures gas to ensure the action will function properly and cycle with blanks. Easy to install and does not alter the M-4 in any way.
Do not use for M-16 family. There is a red blank adapter for the M-16, which has a different barrel length and operating pressure.
Made in the U.S.A. (not imported or "knocked off") and built IAW all relevant MIL-SPECs.