The Cadex M4 extended fore-end rail provides the user with a world-class mount. It is a light and strong rail system. The Cadex rail extension system is produced out of one solid piece of 6061-T6 aluminum and designed for toughness and durability. Its ergonomic design, with multiple rail configurations, allows for great maneuverability and precision improvement. It meets the Mil Std M1913 for rails.