RIS II M4A1 FSP ASSEMBLY BLACK 01-004-08030-006 Manufacturer Model Number: 01-004-08030-006 Manufacturer: Daniel Defense Model: M4A1 RIS II FSP Rail Assembly Type: Accessory-Rails Item Type: Accessory Finish: Black Overall Length: 12.25" Weight: 17.1 oz Shipping Weight: 1.9 Feature: Free Floating Barrel Design Feature: Mil-Spec 1913 Picatinny Rails Feature: Hardened Steel Barrel Nut Optic Adjustable Objective: false Optic Reticle Illuminated: false