Precision Reflex Gen 3 Delta Forearm 15in Carbon Fiber Black. The forearm is constructed of wrapped carbon fiber with an aluminum barrel nut and collar. Total length of the forearm is 7in and weights 13oz. including barrel nut. The clearance from the center line of the barrel to the underside of the forearm is 1.1in. The receiver and the rail on forearm are not at the same elevation. 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 Delta Forearms: Manufacturer: Precision Reflex Fabric/Material: Carbon Fiber/Aluminum/Steel Gun Type: Rifle Gun Rail: Standard Mount Type: Rail Model Generation: 3 Quantity: 1 Package Contents: Precision Reflex Delta Forearms Precision Reflex 05-071-15B: Gen 3 Delta Forearm 15in Carbon Fiber Black