https://www.theverge.com/circuitbreaker/2017/10/4/16425738/google-pixel-2-usb-c-headphone-dongles-20-replacement

Google’s new Pixel 2 and Pixel 2 XL smartphones come with a 3.5mm to USB-C headphone adapter in the box since Google is sadly following in Apple’s footsteps and nixing the traditional audio jack on its newest smartphones.

If you are planning to use your old headphones with your new Pixel 2, you probably shouldn’t lose the free adapter that comes in the box: Google is charging a hefty $20 each for replacement dongles.