HIGH ACCURACY AUDIO INDICATOR Accurate to the 0.1 at 0 and 90 and 0.2 from 189; displays angle and bevel readings in degrees, pitch INFT, mmM, and percent slope. Great for roofs, rails, ADA ramps. Whats more, we craft our digital level with audio indicator functionality, so you can achieve level and 90 degrees even with your eyes closed. Err Message We noticed that some customers flat and level and then showing Err. The 24 inch digital level on the market basically have the X and Y axis, which is a twodimensional measuring tools. The measuring surface is on the silver magnetic Aluminum base. If you place the wrong measuring surface, an Err will be appeared. you can refer to picture 3. 2PM TOOLS products are providing 12 months warranty and life time support, be free to have new item for replacement. DUAL FUNCTIONALITY As a true absolute digital level and electronic inclinometer protractor lets you set or check relative angles between surfaces. Plus, magnetic base firmly attach to ferrous metal surfaces like conduit, pipe, steel construction framing, metal fabrication and more. NEODYMIUM MAGNETS Sturdy solid Ibeam aluminum frame, Neodymium magnets, rubber end caps and IP54 dustwater splash resistant protection for harsh working environments. MEMORY RECALLHOLD FUNCTION Its the fact that it has a memory function that can store your last 8 angle measurements, and how with a hold of a button you can transfer target values to other work areas.