Wet Film Thickness Gauge
Disposable W.F.T. Gauge

Aluminum Size: 2.25" x 3.25"
Range: 1 to 80 mils.Flip Side: 25 to 2032 microns          

How to Use
  1. Place gauge on wet film at 90° angle
  2. Press into film
  3. Withdraw and note deepest tooth having paint on it and next higher tooth that is not coated
  4. The wet film thickness lies between these two readings
  5. Clean gauge in any suitable solvent immediately after use

The drawing indicates that tooth marked 3 mils is covered with the wet paint and tooth marked 4 mils is not covered. This indicates that the true wet film thickness of the material is between 3 and 4 mils thick.