HDP 4 is a D-Class four-channel car audio amplifiers, perfect to satisfy any need. It is the most compact HDP; nonetheless, like the other models, it can reach very high power levels: in less than 30 cm (12 inches) it can provide up to 1000W on 2 channels at 4 Ohm! It can be used in full range as well as with crossover settable as Lo-Pass/Hi-Pass. It has been thought to offer the user the maximum possible flexibility, both thanks to Speaker In and RCA inputs and to the controls, with a status monitor communicating to the user through a LEDs system. Using Speaker In inputs, the ART™ ( Automatic Remote Turn On-Off) function is available; the user can also switch it off. HDP 4 is the perfect choice for those who look for performance and non-bulky sizes. The double-extrusion heat sink and the Hertz logo, which is back lit and can be rotated, allow especially sophisticated installations.