iPhone 7 comes with EarPods that only have a Lightning connector.
If you want to listen through your old headphones, you can plug them in using a 3.5 mm headphone jack adapter.
Pls Note: High copy adapter can only display the iPhone audio. Can't achieve volume control and dial or answer phone call.
If you need the adapter working well pls buy the original quality.
Works with all devices that have a Lightning connector and support iOS 8 iOS 9 iOS 10 or later, including iPod touch,and iPhone