sensor with a long range and usefulness. Thick. Stainless steel and a big plus is that it's magnetic. I can take that to the scrap yard. Attach a flat magnet to it when I go into the yard and check all the metals I want to buy and know the exact thickness and type. .125 inch = 11 caliber. This gauge shows 8 gauges. Still useful, but note that the display is off at 3.