This is a Seymour Duncan acoustic guitar pickup. I'm selling it because I no longer have a use for it. It works perfectly. The following is from the sales site: The SA-3HC employs a hum-canceling design to suppress unpleasant hum noise. Compared to the SC, the full and warm sound is especially recommended for guitarists who frequently use fingerpicking. Double impregnation with wax and epoxy is applied, providing complete feedback protection. Specifications ■ Acoustic guitar pickup ■ WOODY Hum-Canceling ■ D.C. RESISTANCE: 3.50k ■ RESONANT PEAK: 4.8kHz ■ Full and warm sound, recommended for fingerpickers. ■ Compatible soundhole diameter: 3.75″ (94mm) to 4.0″ (100mm) Thank you for looking.