This is the Hobbywing Platinum Pro V4 120A ESC, for use with 500-550 sized Helicopters.

One of a Kind Design
The elegant case is made from aluminum alloy material. Each cooling slot and its fin were carefully designed and arranged, and the case has gone through oxidation, coloring and edge-highlighting.

Innovative Heat Dissipation Structure
The innovative "duo" stacking structure allows all components on both sides of the printed circuit boards to quickly conduct heat to the aluminum case.

Excellent Motor Speed Governing
The high performance 32-bit processor, combined with advanced algorithm, makes the motor speed-governing excellent for different conditions. With the adjustable sensitivity of speed-governing, every pilot can find the most suitable settings for his helicopter.

Super Soft Start-Up
The Platinum 120A makes the motor start extremely soft and avoids tail-drift issues. The start-up time is adjustable within 8 to 25 seconds. This will definitely create a perfect starting point for every flight.

Super BEC
The built-in switch mode BEC with a continuously adjustable output voltage, range from 5V to 8V (steps: 0.1V). It is certain to put out the power you need for rapid, precise steering servo operation.

Great Current Endurance
A high-quality and high-voltage MOSFET with a great current endurance guarantees the ESC's safety especially in a extremely high power demanding situation.

Specifications:
Main Applications: 500-550 Class Helis
Governor: Internal
Built-in BEC: Yes; Switch Mode: 5V-8V, 10A
Continuous Current: 120A
Cell Count: 3-6S
Case: Aluminum Alloy Shell
Programming: LCD Program Box, WiFi Module, via Separate Program Port
Peak Current: 150A
Weight: 107g
Dimensions: 84.3x38.2x20.4mm
DEO Technology: Yes
Spark-Proof: Yes