This is the Savox SH-0255MG Digital Metal Gear Micro Servo.

Features:

Over-spec refined design out performs ordinary micro size servo

• The Aluminum Case design looks good and allows for lower operating temperatures
• Precision metal gears forms a strong and solid framework
• Strict production and quality control of plastic components
• Totally Green – from materials to production, these servos are environmentally friendly
• Idea for CCPM and Rudder on 450 class heli's and 30E Park Flier Airplane's

Specifications:

• Speed @ 6.0V: 0.13 sec/60°
• Torque @ 6.0V: 54 oz-in / 3.9 kg-cm
• Weight: 15.8g
• Bearing: Single
• Type: Micro Plus
• Gear: Metal
• Case: Aluminum
• Output Shaft: 21T Spline
• Case Size (LxWxH): 22.8x12x29.4mm