Cygnus 4PLUS is a small and tough multi-mode ultrasonic thickness gauge which features an A-scan display, simple to use sequential data logging and manual and automatic gain control. Designed for the harshest of environments, with a simple to use keypad, intuitive menus and a colour LCD display which can be viewed in all lighting conditions. The twin shot injection moulded enclosure has a soft but durable TPE outer skin which is comfortable to hold and protects against bumps while the hard internal shell offers maximum strength and environmental protection certified to the demanding US MIL STD 810G standard. The unit still relies on Multiple-Echo to provide simple and accurate measurements, with the added benefit of Echo-Echo and Single-Echo using twin crystal probes for extreme corrosion. Echo-Echo for measurements on painted metals but with heavy back wall corrosion / pitting and Single-Echo for measurements on uncoated surfaces with heavy front face and/or back-wall corrosion and attenuative materials such as cast metals or plastics / composites