This is the HS-35HD Ultra Nano Aircraft Servo from Hitec.
FEATURES: DMK (Dual Metal Karbonite) #3 and 4 gears + 3 Karbonite combination
Dedicated potentiometer and DMK gears ensure long life
INCLUDES: HS-35HD Ultra Nano Servo with two 1.1" (28mm) double arms, one 2.1"
(54mm) double arm, one 1.2" (31mm) double arm, one 0.67" (17mm)
four point arm and three mounting screws
REQUIRES: Installing in aircraft and connecting linkages
SPECS: Operating Speed: 0.1 sec @60°
Output Torque: 11.11oz.in (0.8kg.cm)
Weight: 0.158oz (4.5g)
Size: 0.73 x 0.30 x 0.61" (18.6 x 7.6 x 15.5mm)
COMMENTS: Operating voltage should not exceed 4.8V.