If you have problems with the product you received, please contact us at the first time, we will provide the most satisfactory solution.Model: ESD5500ESpeed range: 1KHz ~ 7.5KHzThermostability: Max.+1%IDLE adjustment: 160±20Hz ~ 95% of rated speedDROOP adjustment: The minimum position is 15Hz +6Hz/ load current change per ampereThe maximum position is 400Hz +75Hz/ load current change per ampereExternal speed adjustment: ±200Hz (external 1KQ)Color: Brown,yellowMaterial: metalPackage Contents:1 * Engine Speed ControllerOnly the above package content,other products are not included.Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.