ZD Fly digital mini gear servo designed for current the fast responses that 450 heli tail requires, and excellent hop-up for those pilots needing quick aileron responses on their airplanes.  Good and inexpensive replacement for DS520.  The servo comes with JR / Hitec / Airtronics (new or Z) style connector.

Digital Servo Specifications
Speed: .07sec/60°
Torq: 34.7oz/in

MAP: $24.99