Complex sentence: The Casio AZ-1 is a polyphonic MIDI keyboard, or keytar, designed to be played, with the aid of a shoulder strap, in an approximation of an electric guitar.
Split into simpler sentences: The Casio AZ-1 is a polyphonic MIDI keyboard in the form factor of a keytar. This instrument is designed to be played, with the aid of a shoulder strap, in an approximation of an electric guitar.