smartwatch, a small smartphonelike device worn on the wrist. Many smartwatches are connected to a smartphone that notifies the user of incoming calls, e-mail messages, and notifications from applications. Some smartwatches can even make telephone calls.. Headphones are a pair of small loudspeaker drivers worn on or around the head over a user's ears. They are electroacoustic transducers, which convert an electrical signal to a corresponding sound.. AirPods (3rd generation) and AirPods Pro (2nd generation) are sweat and water resistant for non-water sports and exercise, and they are IPX4 rated. Sweat and water resistance are not permanent conditions. MagSafe charging requires a compatible MagSafe charger. Wireless charging requires a Qi-certified wireless charger.... loudspeaker, also called speaker, in sound reproduction, device for converting electrical energy into acoustical signal energy that is radiated into a room or open air....