The TA01NSN, a 4x32 ACOG with only tritium night illumination and backup iron sights, is included the Special Operations Peculiar MODification (SOPMOD) kit for the M4A1 carbine used by Special Operations personnel to configure their weapons to individual preferences and mission requirements.
A variant known as the ECOS-N (NSN: 1240-01-495-1385) is also issued as part of the U.S. SOPMOD kit.