These little 2.5gram digital nano servos are another option for the FireFly 2.0. They are new in the market and offer an amazing light weight footprint with an amazing torque of .7kg.cm at 4.8 volts for its size and weight. Although recommended torque for the FireFly 2.0 should be .7 to .9kg.cm, these servos will be great for the FireFly 2.0 if flying at calmer to no wind conditions.
Specs:
Voltage: 4.8~6V
Torque: 0.7kg/cm@4.8V, 0.8kg/cm@6.0V
Speed: 0.08sec/60°@4.8V, 0.07sec/60°@6.0V
Weight: 2.5g
Dimensions: 19.6×8.2×16.3mm
Gears: Plastic
Type: Digital
Servo Plug: JR type
Servo Lead Length: 180mm
Teeth: 20