Adafruit Analog Potentiometer Volume Adjustable TRRS Headset [ADA3959]
Most modern headphone sets are purely digital - with three volume control buttons in-line with the cable. These headphones are interesting in that they have an analog volume control potentiometer. Perfect for use with electronic projects that don't have a volume control, or for phones that don't know how to use the digital buttons. There is one button on the headset, often used for 'pause' or 'mute' - when pressed it grounds the microphone pin.
These earbud headphones are the perfect accessory for your FONA - they've been tested to work with our modules - but can be used with any iOS or Android device that uses a TRRS pinout.
The buds themselves are 16mm in diameter and at a nice 46" long. They come with a standard 3.5mm headphone jack, handy volume control box, and shirt clip.