The Extech TKG150 is a rugged, handheld ultrasonic thickness gauge designed for non-destructive testing of metal structures. It measures thickness from 0.040 to 20 inches (1.0–508 mm) in steel using a 5MHz probe, with optional 10MHz probe for thin materials (0.030–2"). Features include Echo-to-Echo mode to ignore coatings, B-scan cross-sectional view, 100K-point datalogger, vibrating alarm, and IP54 splash-proof housing—ideal for corrosion monitoring in tanks, pipes, and marine applications.