Keyboard: 61 velocity-sensitive (touch-responsive) keys, allowing for more expressive playing based on how hard you press them.Sounds & Styles: Typically includes hundreds of high-quality voices (pianos, organs, strings, etc.) and auto-accompaniment rhythm styles for various genres.Learning Tools: Often features an "Intelligent Learning System" to help beginners practice songs and grade their performance.Connectivity: Includes a USB port for MIDI connection to computers, a headphone jack for silent practice, and sometimes a microphone input for singing along.