The hf3 is designed to work with iPhone and all current iPod models. The main difference between the hf2 and hf3 is the added user benefit of volume control. The 3-button remote control of the hf3 headset makes it easier than ever for a user to pause, adjust and navigate through music tracks on a playlist while exercising, commuting or engaged in other activities. Users can make clear phone calls with the integrated high-sensitivity microphone and adjust volume on the run (sometimes literally) if music selections are not all recorded at the same level.