This is the Savox SH-0257MG Super Speed Metal Gear Micro Digital Servo. Over-spec refined design out performs ordinary micro size servo. The metal case design looks awesome and allows for cooler and smoother operating temps. Metal gears form a solid framework for precise control and operation. Strict production and quality control of plastic components. Our servos are totally green � from materials to production, these servos are . Ideal for CCPM and Rudder on 450 class heli's and park flyer airplanes.