S8911BL 2K with big block top case and bigger gears.
The gears have been upgraded to carborized gears, making them even more durable!
Reinforced and redesigned top case and gears to make the servo more durable ever.  New design helps prevent wiggling pins inside the top case which would create gear gap during flight and would be a cause to damage the gears.
 
 
[Stall Torque]   
 51.7kgs  (6.6V) / 58.0kgs  (7.4V) / 65.8kgs (8.4V)kg・cm
 718.4oz (6.6V) / 805.4oz (7.4V) / 914.3oz (8.4V)oz・in
[Speed]
0.15 (6.6V)/0.13 (7.4V)/0.11 (8.4V) Sec/60°
[Weight]
85.5 g / 3.02 in
[diemension]
35 x 20 x 41.5 mm / 1.38 x 0.79x 1.634 in
[Length of lead harness]
300mm
[Operating Voltage]
4.5V - 8.5V
■programmable
 Neutral, endpoint,gain etc(Works with PWM XBUS)120°150°180°(Works with PWM   XBUS)Synchronize(Works with PWM XBUS)
■Super steel full metal gear(Gear B brass)
■wide voltage
■BIG upper ball bearing (12x6) bottom(10x6)
■Special design Brushless motor
 
Important Notes on Using Our Servos
Our servos are programmed to operate with high precision and sensitivity.
Because of this, if there are any obstructions within the servo’s range of motion and it is unable to move as commanded by the transmitter, the servo may experience excessive load. This can result in damage to the internal circuit board due to overheating.
When installing the servo for throttle, aileron, or other control surfaces, please make sure to leave a small amount of free play between the servo travel range and the mechanical movement range. This helps prevent any binding or overloading of the servo.