Greenlee 200FP Filter Tone Probe By selectively filtering out all 60Hz and 60Hz harmonics, the 200FP can be used with any tone generator for faster, more accurate, cable and wire identification Slim, comfortable design for use in limited-space areas Recessed on/off push-button control to conserve battery life Adjustable sensitivity/volume control to increase accuracy Blended carbon/plastic tip to reduce the risk of shorting terminals