The Reptilia 13" M-LOK Handguard is a premium free-float rail system designed for the AR15 platform and compatible with all M4 upper receivers. It features Reptilia's patented turnbuckle technology, which utilizes a reverse-threaded nut assembly to create high-tension pressure against a standard 1.25-inch driven barrel nut, providing a rock-solid, anti-rotational lockup. Precision-machined from 6061-T6 aluminum extrusion, this lightweight handguard offers seven sides of M-LOK mounting slots and a full-length Picatinny top rail with angled front cuts for improved access to muzzle devices or suppressors. The slim, low-profile design is finished with a rugged MIL-STD Type III, Class 2 hardcoat anodizing to ensure long-term durability in professional or tactical environments. Reptilia 13" M-LOK Black Handguard for M4 Upper Receivers 100-359