JR 8717 or JR8915 super Digita Servo
(Same jr8717)jr 8915 super Digita Servo ( Speed: .09 sec/60° @ 4.8V, .07 sec/60° @ 6V )
Torque: 160 oz/in @ 4.8V. 196 oz/in @ 6V ,- Weight: 2.36 oz

• Gears: Metal
• Blazing speed makes every heli incredibly responsive
• Robust output for superb response in extreme maneuvers
• Zero dead band assures JR's legendary precision
• Metal case helps dissipate heat
• High frequency digital power pulses assure reliability
• Superb holding power
• 35X 21 X 40mm
• 66g

 Asian models are JR jr8915
Exactly the same as with the JR8717

JR DS3517 Digital High Speed Mini Servo Perfect for T-Rex 500
JR's DS3517 fast speed and high resolution provides superior 3D flight characteristics.  High resolution assures precise centering for predictable flying - especially important with large surfaces.  As a cyclic servo in 500-class electric helis, the DS3517 provides a locked-in hover as well as extremely responsive collective and cyclic for extreme 3D maneuvering.
Features:

• Great cyclic servo for 500-class helis
• Great performance for small aircraft
• Nylon gears
• High speed with great torque for outstanding performance
• Digital servo precision

Specifications:

• Type: Digital
• Torque: 42 oz/in @ 4.8V, 51 oz/in @ 6V
• Speed: .11 sec/60 degrees @ 4.8V, .09 sec/60 degrees @ 6V
• Dimensions (WxLxH): .58"x1.02"x1.3"
• Weight: .92 oz
• Bushing Or Bearing: Bearing
• Motor Type: Coreless
• Connector Type: JR
• Gear Type: Nylon

MKS BLS-980 Rudder Servo ( Narrow Band)
Dead band:     0.0004ms (Default)     
Control System:     +Pulse Width Control
Working frequence:     760μs / 560hz       
(RX) Required Pulse:     3.5 ~     6.0 Volt Peak to Peak Square Wave
Operating Voltage:     4.0 ~     6.0 V DC Volts
Operating Temperature Range:     -10 to + 60 Degree C
Operating Speed (4.8V):     0.04 sec/60° degrees at no load
Operating Speed (6.0V):     0.03 sec/60° degrees at no load
Stall Torque (4.8V):     2.5 kg.cm     (34.7 oz/in)
Stall Torque (6.0V):     3.1 kg.cm     (43.0 oz/in)
360° Modifiable:      NO     
Motor Type:      Brushless Motor
Potentiometer Drive:     Indirect Drive     
Bearing Type:     Dual Ball Bearings
Gear Type:     Titanium Gears
Programmable:     NO     　
Connector Wire Length:     24.0 cm     (9.40 in)
Dimensions:     40 x 20 x 40 mm            ( 1.57x0.79x1.50 in)
Weight:      58.0 g     (1.97 oz)

Suitable Gyros：Spartan DS760、Spartan Quark、Futaba GY611、GY601、GY520、ALIGN GP700、GP750、Mikado V-Bar Tail、CSM SL720、Curtis Youngblood Mini-G 、Solid G、Thunder Tiger TG-7000

MKS BLS 950 Cyclic Servo
Dead band:     0.0008ms (Default)     
Control System:     +Pulse Width Control
Working frequence:     1520μs / 333hz       
(RX) Required Pulse:     3.5 ~     6.0 Volt Peak to Peak Square Wave
Operating Voltage:     4.0 ~     6.0 V DC Volts
Operating Temperature Range:     -10 to + 60 Degree C
Operating Speed (4.8V):     0.14 sec/60° degrees at no load
Operating Speed (6.0V):     0.12 sec/60° degrees at no load
Stall Torque (4.8V):     9.2 kg.cm     (127.8 oz/in)
Stall Torque (6.0V):     11.5 kg.cm     (159.7 oz/in)
360° Modifiable:      NO     
Motor Type:      Brushless Motor
Potentiometer Drive:     Indirect Drive     
Bearing Type:     Dual Ball Bearings
Gear Type:     Titanium Gears
Programmable:     NO     　
Connector Wire Length:     24.0 cm     (9.4 in)
Dimensions:     40 x 20 x 40 mm         ( 1.57x0.79x1.50 in)
Weight:      55.8 g     (1.96 oz)

MKS DS 9660 A+ Mini cyclic Servo Perfect for T-Rex 500
Dead Band:      0.0008ms (Default)
Control System:     +Pulse Width Control
Working frequence:     1520μs / 333hz  
(RX) Required Pulse:     3.0 ~6.0 Volt Peak to Peak Square Wave
Operating Voltage:     4.8 ~6.0 V DC Volts
Operating Temperature Range:     -10 to + 60 Degree C
Operating Speed (4.8V):     0.12 sec/60° degrees at no load
Operating Speed (6.0V):     0.09 sec/60° degrees at no load
Stall Torque (4.8V):     3.8 kg.cm           (52.8 oz/in)
Stall Torque (6.0V):     4.7 kg.cm           (65.3 oz/in)
360° Modifiable:     NO
Motor Type:      Coreless Motor
Potentiometer Drive:     Indirect Drive
Driver Type:     FET
Bearing Type:     Dual Ball Bearings
Gear Type:     1 Titanium Gears + 4 aluminum-alloy Gears
Programmable:     NO
Connector Wire Length:     24.0 cm               (9.4 in)
Dimensions:     35.8X15.2X29 mm (1.41x 0.6x 1.14 in)
Weight:      28 g                     (0.99 oz)

MKS DS 9670A+ Mini tail Servo Perfect for T-Rex 500
Dead Band:      0.0008ms (Default)
Control System:     +Pulse Width Control
Working frequence:     1520μs / 333hz  
(RX) Required Pulse:     3.0 ~6.0 Volt Peak to Peak Square Wave
Operating Voltage:     4.8 ~6.0 V DC Volts
Operating Temperature Range:     -10 to + 60 Degree C
Operating Speed (4.8V):     0.088 sec/60° degrees at no load
Operating Speed (6.0V):     0.068 sec/60° degrees at no load
Stall Torque (4.8V):     2.26 kg.cm          (31.4 oz/in)
Stall Torque (6.0V):     2.83 kg.cm          (38.3 oz/in)
360° Modifiable:     NO
Motor Type:      Coreless Motor
Potentiometer Drive:     Indirect Drive
Driver Type:     FET
Bearing Type:     Dual Ball Bearings
Gear Type:     1 Titanium Gears + 4 aluminum-alloy Gears
Programmable:     NO
Connector Wire Length:     15.0 cm               (5.9 in)
Dimensions:     35.8X15.2X29 mm (1.41x 0.6x 1.14 in)
Weight:      27.5 g                  (0.97 oz)