Manufactured To Bcm'S Kmr Barrel Nut Print To Be A Drop In Item For Your Bcm Gunfighter Kmr & Alpha (Keymod Rails). Constructed From Grade 5 Titanium Can Be Purchased Alone Or W/Clamp Block Set Weighs 26 Grams Lifetime Warranty Made In The United States Use With V Seven Ti Kmr Clamp Blocks Mfg: V Seven Weapon Systems