Specifications: Maximum operating voltage: 30V Continuous operating current: 2.5A Instantaneous protection current: 3.5A Working Principle and Usage: It is designed to avoid the potential short - circuit risk between the positive and negative poles of the battery on the circuit board. Since the discharge rate of model aircraft batteries is extremely high, if there is a direct short - circuit in the power supply part of the circuit board, once the battery is directly inserted, the circuit board will catch fire and get charred immediately. On one hand, the circuit board will be damaged; on the other hand, there is also a risk of fire. Before powering on the circuit board, insert this protector into the power supply. If there is an actual short - circuit, it will immediately cut off the main power supply, preventing the circuit board from catching fire and getting charred. Its working principle actually makes use of a self - resetting fuse. If a short - circuit exists, the fuse will heat up and enter a high - resistance state, blocking the current. After the short - circuit point is eliminated and the actual working current is within the protection current range, the fuse will not heat up and will be in a normal state. During normal power - on, the green light is on, the red light is off, and the buzzer is silent. In case of a short - circuit, the red light is on, the green light is off, and the buzzer sounds. It supports the insertion of either an XT30 or an XT60 plug, but only one plug can be inserted at a time. It is not allowed to insert both XT30 and XT60 plugs simultaneously. It is only used during installation and cannot be used during flight. It only protects the main power supply of your circuit board, that is, it is effective for direct short - circuits between the positive and negative poles of the battery. For example, it has no effect on short - circuits of 5V, 12V, or 3.3V on the flight controller. Precautions: Do not set the motor speed to the maximum when the protector is connected to the circuit board. Because at high speeds, the entire working current will far exceed 2.5A, and in this case, the motor cannot reach full speed. Of course, it can operate at low speeds because the current is very small at low speeds. This will not cause damage to the protector, but it may lead to misjudgment, making you think there is a problem with the electronic speed controller. Explanation of the continuous operating current of 2.5A: When connected to the power supply, it will not trigger protection as long as the working current is within 2.5A for a long time. Explanation of the instantaneous protection current of 3.5A: If there is a short - circuit current greater than 3.5A, it will immediately cut off the output power supply. There is also a current range between 2.5A and 3.5A that needs to be explained. Suppose the working current of our load is 3A. What will its state be? In fact, it will trigger protection depending on the power - on time. When it is first connected, it is normal, and it will trigger protection after a while. That's the concept. Of course, there is no need to worry too much here, because in the case of a real direct short - circuit, when the battery is connected, the current will be dozens or hundreds of amperes, far exceeding 3.5A. If you don't like using a multimeter or don't have one, after installation, this protector can quickly help you determine whether there is a direct short - circuit in the main power supply part, reducing the risk of losses. It is especially friendly to novice users. Package Includes: 1*Short Circuit Protector