Check the listing for details. [3DMakerWorld] Adafruit Stereo 2.1W Class D Audio Amplifier - TPA2012. Condition: New. Listed at 17.87 USD. Key Features: Designed for use without an output filter, when wires are kept at under 2"-4" long Four pin-selectable gains: 6dB, 12dB, 18dB and 24dB Excellent click-and-pop suppression Thermal shutdown protection This incredibly small stereo amplifier is surprisingly powerful - able to deliver 2 x 2.1W channels into 4 ohm impedance speakers. Inside the miniature chip is a class D controller, able to run from 2.7V-5.5VDC. Since the amp is a class D, it's incredibly efficient - making it perfect for portable and battery-powered projects. It has built in thermal and over-current protection but we could barely tell it got hot. This board is a welcome upgrade to basic "LM386" amps! The inputs of the amplifier go through 1.0uF capacitors, so they are fully 'differential' - if you don't have differential outputs, simply tie the R- and L- to ground. The outputs are "Bridge Tied" - that means they connect directly to the outputs, no connection to ground. The output is a ~300KHz square wave PWM that is then 'averaged out' by the speaker coil - the high frequencies are not heard. All the above means that you can't connect the output into another amplifier, it should drive the speakers directly. Comes with a fully assembled and tested breakout board with 1.0uF input capacitors. Also included is a dual mini DIP switch for setting the amplifier gain on the fly, 3.5mm screw-terminal blocks so you can easily attach/detach your speakers, and some header in case you want to plug it into a breadboard. You will be ready to rock in 15 minutes! Item Specifics Size (without 0.1" header): 1.11" x 0.19" Weight: 2.56g Output Power: 2.1W at 4 ohm, 10% THD, 1.4W at 8 ohm, 10% THD, with 5V Supply PSRR: 77 dB typ @ 217 Hz with 6 dB gain Speakers are not included, use any 4 or 8 ohm speakers.