This ultrasonic thickness gauge is a portable device used for non-destructive measurement of the thickness of metal and other materials. It uses high-frequency sound waves to determine the thickness of a material by measuring the time it takes for the sound waves to travel from the gauge to the material and back. The r7920 features user-adjustable high/low alarms internal memory capable of storing up to 300 measurements and a simple user interface making it suitable for use by technicians and inspectors in a variety of industries. Features ul style""margin-top0px; padding-top 5px; padding-bottom 5px;"" measures the thickness of steel cast iron aluminum acrylic resin red copper brass zinc quartz glass polyethylene pvc grey cast iron and nodular cast iron easy-to-read backlit lcd display user-selectable units of measure (in/mm) internal memory stores up to 300 measurements displays sound velocity at the touch of a button user-adjustable high/low alarms automatic material calibration auto shut-off and low battery indicator power supply built-in lithium battery (3.7v 2000mah) battery life approx. 16 hours (fully charged) probe length 3' (91cm) probe diameter 0.5"" (12.7mm) accuracy <10mm ±0.1mm10mm ±(1% rdg. +0.1mm) operating temperature 32 to 104°f (0 to 40°c) probe operating temperature 32 to 104°f (0 to 40°c) operating humidity range 20 to 80% storage temperature 14 to 122°f (-10 to 50°c) storage humidity range 20 to 70% includes ultrasonic couplant gel probe usb cable carrying case application monitoring and verifying pipes and pressure vessels industrial manufacturing