Description: Super mini volume: 1.85 x 2.11 cm Excellent noise control. When there is no audio input, you cannot hear any noise even you close to the speaker. Two-channel stereo, single 5V power supply, can directly drive any 4-8 ohms speakers. High output power, good sound quality. Unique non-LC filter Class-D digital power board, can directly use the USB as the power supply. Dual panel wiring, can properly resolve the crosstalk caused by the ground potential balance and channels. Super mini design, can be easily placed within a small place in a variety of digital products. High amplification efficiency. Whole plate welding by machine, high quality. Rated working voltage: 2.5 – 5 V. Limit working voltage 5.5V Package Includes: 1x Audio Amplifier Board Note: The negative part of left and right channel output cannot be connected together, otherwise, the IC will be destroyed. And please connect the speaker (load) before power on.