This complete upper is equipped with Aero's cutting-edge Minimal Optical Deflection (MOD) 4 Handguard, paired with an 18" .223 Wylde PROOF Barrel. Engineered for excellence, this Barrel has undergone rigorous testing to ensure peak performance and unrivaled reliability. Elevate your shooting experience with this precision-crafted complete upper. The MOD 4 Handguard included with this complete upper receiver features a 7 sided M-LOKA(R) interface allows the user to customize this upper to their exact specifications and needs. Lastly, each of the 4 QD sockets on the MOD 4 utilize a steel liner to ensure a higher shear load and longer service life with the continued use of Q Mfg: Aero Precision