This is the ACE RC Standard Metal Gear BB Servo: S1903MG
Each ACE servo is made of high impact materials, so whatever your
application; micro park flyer, trainers, sport, fun fly, scale, giant
scale and helicopters, this ACE servo can more than handle it! This ACE standard servo with metal gears provides
remarkable performance at an exceptionally low price.
Includes: S1903MG Standard Size Servo with Round Horn, Four Point Horn, Double Arm Horn and Mounting Hardware