Precision Reflex Gen 3 Free Float Forearm Round Style Carbine Length Black. 5in rail on top and 3- 3in rails at 36 and 9 O'clock positions. The forearm is constructed of wrapped carbon fiber with an aluminum barrel nut and collar. Total length of the forearm is 9in and weights 14oz. including barrel nut. The clearance from the center line of the barrel to the underside of the forearm is .78in. The inner diameter of the barrel nut is 1.075in Custom barrel nuts with larger ID for larger diameter barrels can be made. Specifications for Precision Reflex Gen 3 Free Float Forearms: Manufacturer: Precision Reflex Fabric/Material: Carbon Fiber/Aluminum/Steel Gun Type: Rifle Handguard Type: Free-Float Handguard Style: Round Rail Gun Rail: Standard Condition: New Mount Type: Rail Model Generation: 3 Quantity: 1 Package Contents: Precision Reflex Gen 3 Free Float Forearms Precision Reflex 05-073-01B: Gen 3 Free Float Forearm Round Style Carbine Length Black