15W+15W Audio Amplifier Board Parameters: Working voltage: DC8-26V, can be operated by DC 12V 24V Output power: 15W stereo (24V 8ohm)/ 10W stereo (12V 8 ohm), if connect 4-ohm or 2-ohm speaker, the power will be automatically limited to 15W Input methods: single-ended (default) difference (to choose by the jumper) Efficiency: >90% THD (total harmonic distortion)&noise: <0.2% Low quiescent current Noise suppression Size: 75.69*41.96mm Materials: high-grade pure black immersion gold circuit board, import WIMA red sound capacitor, each channel large capacity filter capacitor. Special customized pure black copper terminals, gold-plated audio input terminals. Protective functions: input reverse protection, short-circuit protection, over-current protection, over-heat protection, over-voltage protection, low-voltage protection, EMI. Other functions: External mute function (MUTE: High level mute, factory default low level) External turn-off function (SD: Low-level chip turn-off, factory default high level) To use the mute/sd function, just remove the resistance next to the MUTE welding spot and add a switch between the welding spot under the resistance and the welding spot next to MUTE/SD. Stereo Speaker Parameters: Rated power: 15W Impedance: 4Ω Sensitivity: 90dB Effective Frequency: 108Hz-20kHz Equivalent capacity: 2.5L Outer diameter: 78mm Height: 52mm Hole diameter: 71mm Power Adapter Output voltage: DC 12V Package Included: 1x Audio Amplifier Board 2x 15W+15W Speaker 1x 12V Power Adapter 2x Male DC Connector