This is the Hitec/RCD HS-425BB Pro Servo with a Universal Futaba J, Hitec S, JR and Airtronics Z Connector.

FEATURES: Dual Ball Bearings. Indirect Drive. Plastic Gears.

INCLUDES: One HS-425BBS Servo One Servo Accessory Bag (grommets, screws, bushings, horns)

SPECS: Length: 41mm (1.6") Weight: 45.5 (1.60oz) Width: 20mm (0.8") Transit Time: 0.20sec Height: 36.5mm (1.4") Torque: 45.9 oz-in

COMMENTS: This servo shares the same case with the HS-300 servos. The biggest difference is that this servo has dual ball bearings, making it faster, with more torque, and less slop. ir/jl updt  

BOX DIMENSIONS: 3.00" W. X 2.00" H. X 4.00" L. BOX WEIGHT: .14 LBS.