Ab arms rail combo pack ltf 7/5/4 slot rails black FEATURES-Lightweight polymer material-Integrated hardware molded directly into the part to add strength, durability & eliminate the need for additional mounting hardware-Includes a 4 slot rail, 5 slot rail & 7 slot rail-Black Other Features: Works with ab arms handguards and is compatible with mlok.Needs to be installed from the inside out.Also includes hardware for mounting to standard mil-spec m4 profile handguards.