Feature:1. Suitable for standard gauge hole (tachometer) opening, builtin 72x4 watt peak highpower amplifier (28x4RMS) and builtin equalizer with preset equalizer curve (popular classic element).2. With IP66 waterproof certification (tested to withstand various elements), the USB input plays audio files stored on a USB or any other USB device. USB input supports up to 16GB.3. AM/FM radio builtin 18 FM and 6AM presets + American and European tuning, builtin Bluetooth can stream audio from any Bluetoothenabled device.4. Two sets of RCA outputs (front and switchable rear) allow you to connect an external amplifier, USB is 500mA and 5V, and supports charging MP3/WMA.5. Suitable for: cars, motorcycles, yachts, fishing boats, cabins, ski boats, this device is also very suitable for spa pools, quad bikes, club car, UTV, ATV and RV.Specification:Item Type: Digital PlayerMaterial: ABSTechnical Specifications:Use USB, RCA, AM/FM Bluetooth Audio SourceImpedance: 4 OhmFM Stereo Tuner Section Frequency Zone United States, Europe18FM 12AM PresetBluetooth: Long-distance Streaming MusicRms Output Power: 4x40WBacklight Display: YesUV Stable24 Hour ClockPower Supply: DC 12VWaterproof Rating: IP66 CertificationMeet the Astm B117 Salt/Fog StandardMeet ASTM D4329Remote Control Battery: 1 x Button Battery, CR2025, 120mAh, DeliveryWe developed it to give you the best sound and the best features!Very efficient even when operating at 2 ohms!Low distortion even at maximum volumeCrazy loudly:We installed a built-in amplifier, which is louder than other marine receivers on the market. The rms power of the built-in amplifier is 28 watts x 4 channels! When you are on the water, the sound is very great and can be heard in the sound of the wind! There is also a built-in equalizer to customize the sound according to your preferences.latest listening features:GR305 provides you with a variety of listening options. Bluetooth technology allows you to transfer audio from bluetooth-enabled mobile phones or other music players to the receiver. Our bluetooth distance is 50 feet! There is also a usb input that allows you to listen to music stored on the driver. You can plug any audio device into the auxiliary input. There is also a built-in radio, and the reception signal is very clear.Ability to connect multiple external amplifiers:The receiver makes your system scalable. Two sets of preamplifier outputs allow you to connect external amplifiers for the speakers. It has front and switchable rear outputs, so you can amplify speakers and subwoofer amplifiers.amplifier specifications:TDA7851L four bridge power amplifier472 watt peak @ 2 ohm448 watt peak @ 4 ohm428 watts rms @ 4 ohms.Package List:1 x Digital Player2 x Fixing Screw1 x Manual1 x Remote Control