The Midwest Industries Top Rail allows the user to mount an optic and a light or laser while retaining the factory handguard due to the forward M-Lok slot design. Constructed of 6061 aluminum, and hard coat anodized for a lifetime of service. Easy to install with no gunsmithing required. All tools included. Note: This rail is designed to fit 9mm receivers, there may be fitment issues with the 40cal/10mm receivers.