Made of high quality alloy material, sturdy and durable. High temperature resistance, durable and reliable, long service life. How to use: Connect the ESC to the motor - connect the ESC cable to the receiver - turn on the remote control and push the throttle to the highest point - insert the ESC into the battery - listen to the sound - music (123) - beep (confirm the highest point of the throttle ) - after two beeps, pull the throttle stick to the lowest point - hear beeps three times - (confirmation sound for the lowest point of oil, two beeps for 2S, three beeps for 3S) - OK. The three wires of the brushless ESC can be connected arbitrarily. If the steering is wrong, you can swap any two wires. If the three wires are reversed, you only need to exchange any two wires. Please note that this is not an ordinary DC, and cannot be directly connected to the positive and negative poles of the battery or the power supply, otherwise the motor will be directly burned out. Specification: Material:Alloy Size Chart: 27.7x27mm/1.09x1.06inch; Output Shaft Diameter: 3.17mm/0.12inch Package Includes: (optional) A: Motor B: Motor+Cross+Bullets C: Motor+plastic seat+Bullets Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on-line shopping!