Total Measuring Range (depends on material and transducer/probe type): 0.025 - 36.000 inches (0.63 - 914.4 mm); Measuring Range on Steel (with standard T-102-2000 probe): 0.025 - 6.00 inches (0.60 - 150.0 mm). The Checkline TI-25PX Wall Thickness Gauge is designed for measuring wall thickness and the extent of corrosion on a wide range of materials. It is commonly used for checking the thickness of pipes, tanks, plates and other objects. It is designed and built to withstand harsh industrial conditions and is backed by a 5 year limited warranty. The TI-25PX allows the operator to adjust the acoustic velocity (speed of sound through a given material) from 0.0120 to .7300 in/μs. 305 to 18,542 meters/sec. The programmed velocity can be locked to prevent accidental adjustment. It is commonly used for applications where only a single material type is tested.