NDTT The Filler Detective - Automotive Body Filler Damage Detector, Car Body Tester (Red - HOT ROD) Find hidden body damage and body filler on a car, truck or motorcycle Reveal the location and Depth of Body filler, Works with All popular body fillers Measures body filler thickness from 1/16" (62.5 mils) - 1/4" (250 mils) with a step of 1/16" Visual (LED) and Sound Alerts Easy to Use, One Button Operation