The ACE-L-004 Probe and Wire brush is a high-performance, easy-to-use accessory for the standard ACE-L-004 crawler giving highly accurate ultrasonic thickness measurements of underwater ferrous metal surfaces. It can also be used in air with a couplant. The standard probe included with the ACE-L-004 is the Industrial Cygnus Mini ROVTM UT probe, offering sound velocities between 1000m/s and 9995m/s, with accuracy of 0.1mm. Resolution is 0.05mm, and the frequency is 2.25MHz for measuring steel thicknesses between 3mm250mm. Options are available in 3.5 MHz (2mm-150mm) or 5.0MHz (1mm-50mm).