The DeFelsko 200C3-G Positector 200 C3 Advanced Ultrasonic Coating Thickness Gages for Non-Metal Substrates, 2 - 150 mils is DeFelsko PosiTector 200C3-G non-destructively measures a wide variety of applications using proven ultrasound technology. The DeFelsko 200C3-G Positector 200 C3 Advanced Ultrasonic Coating Thickness Gages for Non-Metal Substrates, 2 - 150 mils is PosiTector 200C3-G model measures coating thickness on concrete, fiberglass, etc. Advanced models measure up to 3 layers with graphics.