Amazon.com: Metal Marshmallow Piezo Contact Mic (White +14dB) : Musical Instruments
Amazon.com: Guitar Pickup with Volume Control, Piezo Contact Microphone Transducer for Guitar, Mandolin, Banjo, Cello, Kalimba, Harp and Other Stringed Instrument : Musical Instruments
Contact Mics Contact Microphones Piezoelectronic Transducers Piezo Microphones Weirdo Gadgets Designed by Crank Sturgeon Manufactured by Huso Solutions since 2007
Metal Marshmallow II Piezo Disc Contact Mic and Preamp - Etsy
How to Make a Contact Microphone : 4 Steps - Instructables