[. . . ] How to use / Utilización If you install the Smart Key app* from Google Play store, the track and volume adjustment on your smartphone will be enabled with multifunction button. [. . . ] Ώ Depending on the model of smartphone, the microphone of this unit may not function, or the volume level may be low. Specifications Using the Multi-function button* Available operations for iPhone Press once to answer the call, press again to end; press to play/pause a track. Plays/pauses a track of the connected iPhone product with a single press. Starts the “VoiceOver**” feature with a long press (if available). [. . . ] Optional replacement earpads can be ordered from your nearest authorized Sony retailer or www. [. . . ]