This is the Hitec HS-311 Standard Servo

Hitec HS-311 Economical Standard Analog Servo. The HS-311 sport servo provides the novice modeler all the performance and reliability you would expect to find in a more expensive servo. Combined with precise resin gears and SMT circuitry, the HS-311 represents a remarkable value in today's R/C market. This version of the servo has a universal connector which will fit Airtronics, JR, Hitec and Futaba receivers (be careful with the polarity of the connector for Futaba radios).

Specifications:

• Speed:
• 4.8V: 0.19 sec/60 deg.
• 6.0V: 0.15 sec/60 deg.
• Torque:
• 4.8V: 42 oz/in
• 6.0V: 51 oz/in
• Weight: 1.5oz (43g)
• Length: 1.4" (37mm)
• Width: 0.8" (20mm)
• Height: 1.6" (41mm)