The Hertz X 690 from the Uno series is a 4-way coaxial speaker system designed specifically for installation on a car's rear shelf. These 6 x 9 inch oval speakers are built for high sensitivity, allowing you to achieve a loud and clear output even when using a basic factory head unit without an external amplifier. Inside the assembly, a large area oval diffuser handles the low and mid frequencies, while the high end is managed by a 40 mm cone tweeter and two 15 mm piezoelectric super-tweeters, all featuring polyetherimide diffusers. This configuration, combined with specialized lens diffusers, helps expand the radiation angle to fill the cabin more effectively. The system operates with a nominal power of 85 W and can handle peaks up to 340 W, covering a frequency range from 45 Hz to 22 kHz at 4 Ohm impedance. To ensure durability in the demanding environment of a vehicle, the speakers are housed in a steel basket protected by a powder coating that resists scratches and corrosion. This makes them a practical choice for drivers who want to upgrade their audio experience with hardware that is both robust and efficient.