... to 1200s as customer needOperation: Press buttonsCertification: CE ROHS SGSBattery: Button cell, AA,or AAASample time: 4 to 10daysMass production: 30 days ... be heard when you pressing the relative keys5. Different sound button control different sound or the chapters and sections6. Fit ... module inside the book, it can send out by pushing button,light sensor.8. Custom sound, housing design are welcome. ...