The device has already "paid off" within a week for us. In the middle of the planning phase for collection in our new condo there in seconds "distance information" (fits the wardrobe, the PC, the printer while ..?) - In the application no bückendes attachment of ruler or measuring tape abknickendem more. The function is self-explanatory after a single reading of the manual. The there also recommended "calibration measurement" is a gratifying result of measurement: namely, a true, precise data information in the balance for the ruler. - what more do you want ? (Am a layman and technically a "zero")