Generates strong, pulsating ultrasonic sounds that are perceived as very annoying by martens and other rodents, thereby driving them away. This marten repeller comes with four small ultrasonic speakers to ensure a good distribution of the ultrasonic sounds. If a marten protection device is installed in just one location in the engine compartment, "sound shadow" can occur due to the engine. Distributing the speakers in different locations can prevent this. The cables to the speakers can be up to 50 meters long.