This is a Odin Works Forend known as the Ragna, model F-15-ML-RA.
Different than any forend ODIN Works has ever made" the Ragna is a complete change from past forends. Literally designed for the fastest install possible" the RAGNA features a one piece barrel nut with no shims or clocking needed. Available in 12.5" 15.5" and 17.5 inch lengths" the RAGNA will make any build better. Strong" lightweight" and unique" the RAGNA is available with MLOK or KMOD attachment points where you need them.
Features:
Free floating
Type 2 Hard Anodize
Once piece barrel nut, Black Nitride coating
All mounting hardware included
Accessory rail not included
Made from 6061T6 aluminum
Inside Diameter: 1.35";Outside Diameter: 2.02 Tall by 1.52";KMOD or MLOK available at 3, 6, and 9 o'clock;All .750 ODIN Works gas blocks fit inside;Weighs just 10.35oz installed (including barrel nut)