On Sight Armory's 15" MLOK handguard has 5 slot rail in the front and a 4slot rail on the rear that  allows you to mount iron sights, optics, and any other accessories without additional railing sections. The MLOK system allows users to personalize the hand guard with railing sections and guide attachments. The hand protector is constructed of 606T6 aircraft aluminum & completed with a hard coat black anodizing. Has a precision bore at match with the barrel nut that removes any play and ensures an solid fit. Installation takes a crows foot wrench for the barrel nut; standard AR-15 socket nut wrenches won't work with this particular hand guard system.
 
 
Features:
Material: Hard Coat Anodized Aluminum Handguard, 6061-T6 Aluminum Barrel Nut
Precision Bore
1913 Picatinny Continuous Top Rail Sections
Accepts Keymod Rail Sections & Accessories 
Requires 1-1/8" Crowfoot Wrench and Medium Strength Thread Locker (not included)