Savox .15/277.7 Aluminum Case Waterproof Coreless Digital Servo Combines leading edge technology with super high 12 bit (4096) resolution and steel gears Waterproof construction keeps out the elements for worry free operation Coreless motor provides high speed, incredible efficiency, and low power consumption Extremely strong steel gears ensure long-life and durability The aluminum case design not only looks good but also allows for cooler and smoother operating temps