Reptilia M-LOK Handguard 15in Black. The handguard is compatible with all M4 upper receivers and comes in M-LOK configuration. The handguard will be available in 4 lengths and includes the required barrel nut and hardware. As with all Reptilia products the handguard is made in specialized factories and includes a full lifetime warranty against manufacturer defects. Barrel nut Torque Spec: 50 ft-lbs. Turnbuckle Torque Spec: Hand tight with red thread locker Specifications for Reptilia M-LOK Handguard: Manufacturer: Reptilia Gun Model: AR-15 Features of Reptilia M-LOK Handguard Handguard with Turnbuckle Technology Compatible with Ar15/M4 Uppers Made from 6061-T6 aluminum extrusion MIL-STD Type III Class 2 hard anodized Package Contents: Reptilia M-LOK Handguard Reptilia 100-339: M-LOK Handguard 15in Black