... sensor, vibration sensor, shadow sensor or rocking switch.Main component: speaker, PCB, IC, batteries, switch, wiresSpeaker available: 40mm, 29mm, 27mm,21mm ... down the yellow paperStep 3: stick on the greeting cardStep 4: close the greeting card and re-open, then the music ... producing electronics products since set up in 1996, more than 4 years experience dealing export business.2. We are a well ...