This device is a small USB buzzer. You can control both the frequency and the volume. There is even a way to preset simple beeping patterns.
In addition, the Yocto-Buzzer also features two bright leds (one red + one green) and two analog inputs able to read any resistive sensor such as switches, push buttons, potentiometer, reed contact, photo diodes, and so on...
Long story short, the Yocto-Buzzer is the device that you need to get your user to pay attention, especially if your project is driven by a headless computer.
USB cables and enclosures to be ordered separately.