Mini External USB Stereo Speaker : ID 3369 : $12.50 : Adafruit Industries, Unique & fun DIY electronics and kits
Adafruit Speaker Bonnet for raspberry pi - Share Project - PCBWay
Using a Speaker for Audio Output | Mbed
Amazon.com: Portable Mini USB Speaker Dual Horn Units Computer Speaker Sound Box with Sound Card Decoder USB Sound Card Decoder Audio Input(Black) : Automotive