Natural, detachable passive piezo pickup solution for violin and viola with volume control Encased in lightweight tone wood, the VV-2 sensor ensures the natural amplified sound of your instrument. VV-2 installs easily and safely in the eye of the viol bridge with minimal modification. VV-2’s built-in potentiometer allows sound level adjustments from the stage. Adjustable input jack housing clamps are lined with soft, protective cork. VV-2 conveniently accepts a 1/4″ cable jack.