Mini Analog Thumb Joystick
This is a small joystick with a black rocker cap, similar to the ones used in Nintendo joycons. Note it is NOT a replacement for Switch Joycons, it just has the same feel and sizing. The joystick is a 'self-centering' analog-type. It is comprised of two 10KΩ potentiometers, one for up / down and another for left / right. There's also a center 'press' tactile button for selection.
You can solder the potentiometer pins onto a custom breakout board if you so choose - note it is 2mm pitch not 2.54 so not breadboard-friendly.
When fully assembled and functioning, the voltage will follow the motion of the thumbstick as it is moved around. When you release the thumbstick it will center itself. Great for robotics and other control interfaces!