The KST 08 MG Servo features a high voltage capable motor & electronics, an oversized large 8mm output motor that provide great torque and high speed. Voltage input can be from 3.8V to 8.4V. 
 
Version 5 incorporates updated firmware and electronics, allowing for an incredible amount of precision over the previous Version 3. 
 
Features:
Micro size aluminum case
Full metal gears
Dual ball bearings
HV compatible
Lightning fast
8mm Coreless motor 
 
Specifications: 

Operating Voltage: 3.8-7.4V 
Size: 29.5x25x8mm (width x height x thickness) 
Torque: 2.20kg.cm @ 6.0V; 2.80kg.cm @ 8.4V 
Speed: 0.15sec/60° @ 6.0V; 0.09sec/60° @ 8.4V 
Weight: 8.4g 
Working Frequency: 1520us/333Hz, 800us - 2200us 
Motor: Coreless 
Ball Bearing: 2BB