An easy-to-install preamp soundhole system for steel string and classical guitars. It comes with a Nanoflex pickup that not only responds to string vibrations, but also senses the vibrations of the body of the instrument simultaneously. This completed shielded system incorporates active amplification in the pickup itself, which makes it 100% hum and noise free. The SH Sonic NFX also comes equipped with a phase switch, which rotates the frequency curve 180 degrees and eliminates feedback.