The American Built Arms A*B Pro Handguard is a two piece drop-in design with integrated upper and lower heat shields. The proprietary heat stabilized nylon construction is reinforced with high strength fibers and offers modularity, accepting standard picatinny rail sections (sold separately). The top rail section provides options for mounting optics, lights, and other accessoriesFeatures2 piece, drop-in design for round ModularErgonomicWorks with gas piston or direct impingement systems