AGFrc B11DLS 21T Micro High Torque Servo, with brushed motor, single bearing and steel gear to keep the smooth operation.
It is a high performance digital circuit micro servo, it can reach 2.8 kg-cm high torque and a 0.10sec speed at 6.0V. 

Feature

High Performance Digital Servo

Upgrade Reliable Steel Gear

High Quality Brushed Motor

Ideal for Car, Airplane, Helicopter, Robot

Specification

B11DLS

Operating Voltage: 4.8-6.0 V

Operating speed: 0.12ec/60° @ 4.8V

Operating speed:  0.10sec/60° @ 6.0V

Stall Torque: 2.2 kg-cm (30.55 oz-in) @ 4.8V

Stall Torque: 2.8 kg-cm  (38.88 oz-in) @ 6.0V 

Motor type: DC

Gear type: Steel

Size: 23*12.1*23.8mm (0.9 x 0.47 x 0.93 in)

Weight: 13.8g 

Connector Wire: JR 180 mm