Smartwatches with speaker and microphone (phone calls)

Speakerphone

— the ability to operate the gadget in traditional hands-free mode, using the built-in speaker and microphone for conversation. In conventional smartwatches (see "Type"), this feature allows you to talk without taking your smartphone out of your pocket; in watch-phones, it allows you to do so without headphones and headsets. However the volume of the built-in speaker is usually low, so in a noisy environment its power may not be enough.

Note that beacons for children in this paragraph are not taken into account at all: for them, speakerphone is almost mandatory. More precisely, by definition, it exists if the beacon supports mobile communications and has a slot for a SIM card — and these features are provided in almost all children's gadgets.