Features: 1.Suitable for standard gauge hole (tachometer) opening, built?in 72x4 watt peak high?power amplifier (28x4RMS) and built?in 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 built?in 18 FM and 6AM presets + American and European tuning, built?in Bluetooth can stream audio from any Bluetooth?enabled 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 Player Material: ABS Technical Specifications: Use USB, RCA, AM/FM Bluetooth Audio Source Impedance: 4 Ohm FM Stereo Tuner Section Frequency Zone United States, Europe 18FM 12AM Preset Bluetooth: Long-distance Streaming Music Rms Output Power: 4x40W Backlight Display: Yes UV Stable 24 Hour Clock Power Supply: DC 12V Waterproof Rating: IP66 Certification Meet the Astm B117 Salt/Fog Standard Meet ASTM D4329 Remote Control Battery: 1 x Button Battery, CR2025, 120mAh, Delivery We 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 volume Crazy 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 amplifier 472 watt peak 2 ohm 448 watt peak 4 ohm 428 watts rms 4 ohms