The audio adapter is designed for the Sonim Bolt XP5560:

• Sonim Bolt XP5560

If you prefer to use a 2.5mm headset with your Sonim Bolt XP5560 cell phone, you will need to plug in the 2.5mm audio adapter in order for the headset to work. Just plug this audio adapter into your cell phone to convert the audio. This adapter allows you to use a 2.5 headset with your Sonim Bolt XP5560 phone.

• Easily installs; simply plug the audio adapter into your Sonim Bolt XP5560 cell phone audio jack; then plug in any 2.5mm, two ring headset into the audio adapter