Back reading means no making holes in the substance being measured. Hold it flat to the area in question and you get a percentage readout instantly. Slide it around a wall or ceiling and you get instant results. We have an RV and there was a leak in the roof. I needed to know if I had to tear apart the roof or not and if so how much. I hoped to drive the moisture out after sealing up the outside. I opened some ventilation spots and ran a heater. I was able to watch the moisture levels drop until it was OK. I could also see where the problem areas were. These are also good to see what the water content of lumber is. Checking a boat for waterlogged hull. Checking a ceiling for leaks before any damage shows.

Detected wet areas behind a wall. Had the drywall removed only to find metal that was probably causing it to go off. I don't think this is unique to this brand but more to the technology of these moisture detectors that do not use probes. I had a "professional" detect the leak with a different brand prior to my purchasing this item. I purchased this tool to confirm their findings only for both of us to be wrong.

I can't speak to the accuracy. As for the other things: OPERATION: Simple to use. No manual required. Don't have to enter the species of wood, just choose either Hardwood or Softwood (or Drywall or Masonry). BATTERY: Requires a screwdriver to open the battery cover. That's a gratuitous annoyance. Battery covers should always be openable without a screwdriver unless the item is a toy for small children who might swallow the battery. PACKAGING: Uses hard plastic bubble which is non-renewable and a pain to open. There's been a trend now for years towards "frustration-free" packaging. Klein is behind the times.