The Armalite M15 Competition Handguard kit is ultra-light and is designed with a slim profile for maximum comfort with minimum weight. The rail features full-length Key-Mod attachment points double as flush-cup sling mounts for endless customization with a wide variety of accessories. This kit includes barrel nut, mounting hardware, and instructions for easy installation.
Armalite calls this is their 12″ hand guard. It does measure 12.5″ from end to end on the picatinny rail. Their measurement is likely from the chamber to the end of the hand guard.