This is the Savox SW-1210SG "Tall" Waterproof Aluminum Case Steel Gear Digital Servo. The SW-1210SG is a coreless, waterproof digital servo that delivers great torque for applications that use a larger 42mm tall servo. This servo features a speed of .15 and 277.7 oz-in of torque @ 6.0V. It combines leading edge technology with super high 12-bit (4096) resolution and metal gears for greater precision when dodging puddles. This is a great upgrade if your looking to drive your RC vehicle in any condition, including rain, sleet, or snow.  Features: 

• Combines leading edge technology with super high 12 bit (4096) resolution and metal gears
• Waterproof
• High Voltage 7.4V Compatible 
• Coreless motor
• Extremely strong metal gears ensure long-life and durability
• Totally green – from materials to production, these servos are environmentally friendly.
• Ideal for RC cars, trucks, buggies, and boats

Specifications:  Dimensions (mm): 40.6x20.7x42.0  Weight (g): 71  Speed @6.0V: .15 sec/60  Speed @7.4V: .13 sec/60  Torque @6.0V: 277.7 oz-in (20.0kg)  Torque @7.4V: 444.4 oz-in (32.0kg)  Gear: Unique Steel  Bearing: 2BB  Case: Aluminum middle  Output Shaft: 25 Tooth Spline