Model TI-25S comes preprogrammed with sonic velocities for aluminum 2024, stainless steel 303, steel 4340, cast iron, plexiglass, PVC, polystyrene and polyurethane. Measuring range is 0.025 to 19.999 in. and resolution is 0.001 in., Ultrasonic wall thickness gauge is switch selectable between English and metric units and displays results in inches, inches/microsecond, millimeters, and meters/second. Alkaline or NiCd batteries provide power for up to 200 hr of use.