Andoer QH-6B 12-hole Magnetic Sound Hole Guitar Pickup Transducer Kit with Volume Controller Lapel Tie Clip Microphone Audio Cable for 38"/39"/40"/41" Acoustic Guitar 12-hole magnetic transducer captures vibrations quickly and converts mechanical vibrations to an electrical signal. Easy to install, put pickup into sound hole and adjust padded metal piece to fix it stably without scratch and need of drilling hole. Passive design, without need for external power. Lapel clip microphone with cable of about 1 meter allows you to sing while playing guitar. Comes with an audio cable (3.5mm-6.5mm), approx. 3 meters in length.