Gel Coat Thickness GaugeOur gel coat thickness gauge is the perfect tool for measuring wet mil thickness as you apply your gel coat. It reads in both mil scale (1 80 mils) and microns (25 2032 microns) and allows you to achieve repeatable high quality results. This is the most accurate way to measure your gel coat and ensure that you're obtaining the desired thickness. Simply place the edge of the tool into the wet film the last tooth marked is your wet film thickness.