Sound hole mount humbucker pickup for steel string acoustic guitar. NanoMAG pickups are low-impedance active mini-humbuckers made with Samarium Cobalt magnets. These innovative Shadow pickups are balanced for both acoustic and electric guitar strings and have a much larger frequency range than your typical midrange-heavy humbucker. This easy-to-install and height-adjustable pickup can be rotated inside your guitar’s soundhole to alter tonal response. Height adjustable 0mm to 15mm, Easy installation, Integrated endpin, Large strap button (D = 16.5 mm) For sound hole diameters: 96 to 105 [mm] Passive, no battery required, DC Resistance: 5.28kOhm, B-string volume compensation.