The compact ultrasonic wall thickness gauge C1 EX is operating according to the multi-echo-technology. It measures reliably through colour layers as well as protective coats. The device is intrinsically save. It was developed for the precise non-destructive testing of the wall thickness of materials such as glass, metal, ceramics and plastics in hazardous areas. The C1 EX tests pipes, tanks, machine- and steel parts as well as pressure tanks for wear. A zero point adjustment is not necessary. The robust watertight device measures even at rough, cragged surfaces accurately.