Sustain
The presence in the keyboard of its own sustain control — the extension of the extracted note. With sustain on, the note continues to sound (slowly decaying) even after the key has been released—similar to depressing the right pedal on a piano. Note that many keyboards allow the connection of pedals, including to control this function (see "Connected Pedals"), however, here it means its own controller, which allows you to turn sustain on and off using the keyboard itself, without additional equipment.
Bluetooth
Wireless interface for direct communication between devices. Models with such an interface usually allow connection not only to computers and laptops equipped with
Bluetooth modules, but also to portable gadgets like smartphones or tablets (if appropriate applications are available). In this case, the communication range is several metres (up to 10 m within the line of sight), and the absence of a wire eliminates the hassle of connecting and provides additional convenience.