It is essential that ultrasonic couplant is used when taking thickness measurements (although not needed underwater). Couplant ensures that there are no air gaps between the probe and the surface being measured.
We supply UCA-2M Ultrasonic Couplant which is a thixotropic, water-based, blue gel which is non-hazardous. It is available either in a 1 litre tub or 100ml flip-top bottle, ideal for carrying on site.
UCA-2M 1litre tub P/N 001-3707
UCA-2M 100ml P/N 001-3708