Feature: 1. Can transmit music from mobile phone, tablet PC or other BT-enabled audio devices to your speakers via BT connection, no wire needed. Transmission range is up to 30 feet. 2. Simple and convenient to select AUX IN mode and BT / USB Reader mode with one switch. Freely to control volume with a volume control knob. 3. The output power of this digital audio power amplifier is 50W + 50W, dual-channel output. Left and right channel negative pole cannot be connected. 4. Adopts the professional high-quality WIMA MKP10 capacitor; Using large capacity 1000uf high-frequency low resistance output capacitor, giving you amazing HiFi music. 5. High-quality aluminum alloy case, gold-plated input and output interface, exquisite and durable. Specification: Features: Can transmit music from mobile phone, tablet PC or other BT-enabled audio devices to your speakers via BT connection, no wire needed. Transmission range is up to 30 feet. Simple and convenient to select AUX IN mode and BT / USB Reader mode with one switch. Freely to control volume with a volume control knob. The output power of this digital audio power amplifier is 50W + 50W, dual-channel output. Left and right channel negative pole cannot be connected. Adopts the professional high-quality WIMA MKP10 capacitor; Using large capacity 1000uf high-frequency low resistance output capacitor, giving you amazing HiFi music. High-quality aluminum alloy case, gold-plated input and output interface, exquisite and durable. Specifications: Model Number: NK-368R BT: 4.0 BT Effective Range: about 10 meters Channel: 2.0 Output Power: max. 50W * 2 SNR: ≥80dB Sensitivity: 750mV T.H.D: ≤0.1%（1kHz） Frequency Response: 20Hz-22KHz Power Supply: Input--100-240V 50/60Hz, output--19V 3.42A Material: Aluminum Alloy Color: Silver, Black (Optional) Item Size: 12 * 9.5 * 3cm / 4.7 * 3.7 * 1.2in Item Weight: 337g / 11.88oz Package Size: 24.5 * 18.6 * 6.7cm / 9.64 * 7.32 * 2.63in Package Weight: 768g / 27.09oz Package List: 1 * Amplifier 1 * Power Adapter 1 * AC Cable Package List: 1 * Amplifier 1 * Power Adapter 1 * AC Cable