Only works with rear charging upper receivers. M-lok Style Handguard RailUltralight Stye, Fit .223/5.56 Rifle15" length free float rail mount with partial Picatinny Top rail and M-LOK slot system. Two MLOK rail mounts included. CNC machined from Quality aluminum. {{widget type="Magento\Cms\Block\Widget\Block" template="widget/static_block/default.phtml" block_id="42"}} It is the responsibility of the consumer to ensure all state, local, federal, and ITAR regulations are followed