This is the HS-5055MG Sub Micro Digital Feather Servo from Hitec.

• Programmable
• Overload protection
• Metal gears
• Lightweight
• Ideal for park flying models, indoor planes, small glider, and micro electric helis

• One Hitec HS-5055MG Micro Digital Feather Servo with preinstalled small X-shaped servo horn and screw
• One 28mm straight servo arm
• One 31mm servo arm
• One 54mm servo arm
• One 1.6x3.75mm button head screw
• Two 1.7x8mm flanged button head screws

• Speed: 0.20sec/60 degree at 4.8V
• 0.17sec/60 degree at 6V
• Output Torque: 1.3kg-cm (18.05oz-in) at 4.8V
• 1.6kg-cm (22.20oz-in) at 6V
• Weight: 9.5g (0.33oz)
• Size: 22.8 x 11.6 x 24mm (0.89 x 0.45 x 0.94in)