The PVA 4307 is a stereo active loudspeaker system with 4 x 2.75'' wide range speakers. Aluminum cone diffuser. Built-in Class D amplifier with DSP processor. Max. sound pressure level 95 dB, frequency range 40 Hz - 20 kHz. Input: 2xRCA (socket). Automatically switches on when there is an input signal for more than 3 seconds. Turns off automatically if there is no input signal for more than 15 minutes. Remembers the sound level when switching off. There is an automatic input level limiter. Control port: RS-232, RS-485. External power supply. Profile is made of high quality anodized aluminum. Black color.