Speaker

Portable or stationary speakers that can connect microphones and offer functions such as echo/reverb for singing.

The maximum time the speaker can operate playing music on a full charge under ideal conditions. (e.g. the manufacturer may have measured this at low volume)

Features built-in LED lighting for an enhanced aesthetic experience.
For example, in some speakers, the lighting can follow the music and change colors and intensity rhythmically.

Wireless

Ability to connect the microphone wirelessly (e.g. via Bluetooth or receiver) to the sound unit.

Remote control for easy and remote operation of the device