ET150 uses contact pins and includes wood and building-material modes. That makes it a different observation method from the pinless ET140. Decide whether the surface can accept small marks before measuring, particularly on visible finishes or someone else’s property.
The protective cap includes a calibration-check function, and the listed package includes spare pins and two AAA batteries. Keep the cap with the tool so the manufacturer’s check can remain part of your routine. Use that check as directed and record the material and mode with each measurement.
Note the material, selected mode and measurement location. Do not compare a building-material reading with a room hygrometer’s relative-humidity percentage or treat one reading as proof that an entire assembly is dry. Compare the method and material rather than treating one number as a ranking of both meters.
