Amazon.com: Piezo Pickup/Pre-Amp Unit for Acoustic Guitars EQ-7545R : Musical Instruments
G tone 2 band Ukelele EQ Ukulele Equalizer Pickup Hawaiian Guitar EQ with Tuner Pickup Piezo Ceramic Pick up Preamp System|Guitar Parts & Accessories| - AliExpress
Endpin Jack Style Piezo Pickup Pick-up Preamp System with Tone Control for Acoustic Guitar - Walmart.com - Walmart.com