Marine Grade Protection / IPX Rating - Meets or exceeds IPX5 requirements for water and dust proofing. Apple Control - Quick control and access of music apps via iPhone, iPod and iPad. Source Type - AM/FM/Bluetooth Radio allows all access to radio stations and content from Bluetooth enabled devices. Input Types - Bluetooth, RCA, USB: Nearly nothing the device can not play. Control Buttons - Front facing buttons to engage and adjust all features. Secure Simple Pairing - Quick and secure wireless connection between your Bluetooth enabled device. This reliable connection is impervious to outside interference, providing a lock-tight connection to your audio system. Control Method - 9 control buttons on faceplate. Frequency Range - FM: 87.5-108, AM: 530-1710 Additional Inputs - 1 Pair (Aux), 1 USB USB / Apple / Charging Port - 1 USB Bluetooth Version - Version 4.0 Source Unit Tuner Section FM Stereo Frequency Range: 87.5MHz-108MHz Source Unit Tuner Section S/N Ratio: 86.4dBA Source Unit Bluetooth Range (ft): 32 Source Unit RMS Power Output (watts): 4 x 16 Source Unit Peak Power Output (watts): 4 x 40 Source Unit S/N @1W: 90.6dBA Source Unit Frequency Response (Aux In): 20Hz-20kHz Source Unit Pre-amp Outputs (Y/N #): 1 Pair, Yes Source Unit Pre-amp Voltage: 5.9V Source Unit Minimum Impedance (ohms): 4 Source Unit Dimensions Mounting Hole (in): 7.0 x 2.0 Source Unit Dimensions Total Mounting Depth (in): 4.5 Additional Details: MAXIMUM THD+N AT 4 OHMS: 15.8 watts MAXIMUM UNDISTORTED PREAMP VOLTAGE (WITH 20K OHM LOAD): 5.9 Volts SIGNAL TO NOISE (CTA-2006B): -86.4dBA AUX / -84.7dBA Bluetooth SIGNAL TO NOISE RATIO OF LINE LEVEL OUTPUTS (AT MAX VOLUME): Bluetooth -88.4dBA / Aux -90.6dBA PREAMP FREQUENCY RESPONSE (+/- 3.0DB): 20Hz–19.5kHz AUX / 34Hz–15.6kHz Bluetooth AMPLIFIER FREQUENCY RESPONSE (+/- 3.0DB): 20Hz–20.0kHz AUX / 27Hz–20.0kHz Bluetooth STEREO SEPARATION (AUX INPUT): -65.1dB @ 5kHz FM MONO USABLE SENSITIVITY: 12.7dBf AM MONO USABLE SENSITIVITY: 12-14µV