Guntec USA Ultra Lightweight Thin M-LOK System Free Floating Handguard w/Monolithic Top Rail 4in Blue. Guntec USA machined these AR Handguards & Forends from rugged lightweight T6 aluminum with an added anodized finish to further enhance their strength and resistance to corrosive elements. For optimal performance this GUNTEC USA Ultra Lightweight Thin M-LOK Free Floating Rifle Handguard w/Monolithic Top Rail delivers a tight fit up against the receiver and the top rail is the perfect platform to host optics and other useful accessories. Improve your weapon with this ergonomic GUNTEC USA Ultra Lightweight Thin M-LOK System Free Floating AR-15 Handguard w/Monolithic Top Rail. Specifications for Guntec USA 4in Ultra Lightweight Thin M-LOK System Handguard w/ Monolithic Top Rail: Manufacturer: Guntec USA Fabric/Material: T6 Aluminum Gun Make: AR Platform Gun Model: AR-15 Gun Type: Rifle Handguard Type: Free-Float Gun Rail: Monolithic Top Rail Inner Diameter: 1.34 in Outer Diameter: 1.5 in Height: 2 in Mount Type: M-LOK Features of Guntec USA 4in Ultra Lightweight Thin M-LOK System Handguard w/ Monolithic Top Rail M-LOKsystem Rail system slides over barrel nut and is locked up against receiver with 6 screws Tight fit up against receiver which allows for a monolithic picatinny top rail Heavy duty Package Contents: Guntec USA 4in Ultra Lightweight Thin M-LOK System Handguard w/ Monolithic Top Rail Proprietary Barrel Nut Included Guntec USA GT-4MLK-BLUE: Ultra Lightweight Thin M-LOK System Free Floating Handguard w/Monolithic Top Rail 4in Blue