Sons of Liberty Gun Works M89 M-LOK Handguard 11.5" Fits AR Rifles Anodized Finish Black. This system clamps the rail onto the steel barrel nut with extreme force and precision" while also driving the handguard rearward towards the upper receiver. The slightly larger ID of that extrusion gives you more real estate around the gas block" even more rigidity than the M76" and takes longer to heat. Specifications for Sons of Liberty Gun Works M89 M-LOK Handguard: Manufacturer: Sons of Liberty Gun Works Color: Black Finish: Anodized Black Gun Make: AR Platform Handguard Length: 11.5 in Gun Rail: M-LOK Additional Features: Handguard Case Finish: Anodized Handle Color: Black Blade Finish: Anodized Handle Finish: Anodized Size: 11.5 in Features of Sons of Liberty Gun Works M89 M-LOK Handguard: Hard Anodized Finish Black Package Contents: Sons of Liberty Gun Works M89 M-LOK Handguard