Bravo's kmr alpha is constructed of aluminum with a hardcoat anodized finish for corrosion resistance and is free-floating.Its interface system was developed to work in parallel with the current picatinny system.This rail system allows for a larger range of modularity offering four different offset mounting positions between traditional 3,6,9, and 12:00 positions.Included is a bcm keymod sling mountType: HandguardFirearm Type: RifleFirearm Model: AR-15Material: AluminumFinish: Black Hardcoat AnodizedFeatures: KeymodPositions: 4Free Floating: Yes