Official Apple Lightning to 3.5mm Jack Adapter
Official Apple Lightning to 3.5mm Headphone Jack Adapter.
If you want to use your own headphones, but have an iPhone with NO 3.5mm jack (most of them these days) this is the perfect accessory for you.
With a Lightning connection on one end, and a female 3.5mm Jack connector on the other, just simply plug it in to you iPhone, and then connect your headphones.
Connectivity: Lightning to 3.5mm Jack Adaptor