The app is able to calculate the value of the resistors to be purchased and use on the LEDs that you want to mount in your car. The absorption of LEDs is different from the original light bulbs, and often there are problems such as: flashing of the LEDs themselves, perennial ignition dimly, strange behaviors during the use of the direction arrows and much more. Now you can easily know the exact value of the resistance that will avoid all the problems related to the replacement of LEDs in the car.