The Universal Tape Gauge (a.k.a. U.T.G.) by Dowelmax solves the age-old problem common to all tape measures, allowing you to easily and accurately take an inside measurement. No longer will you need to bend the tape into a corner and guess what the measurement should be. Make your tape a more versatile, accurate measuring instrument for measuring inside corners of crown molding, baseboards, shelf units, area calculations, window frames, and more. Compatible with 99% of all existing tape measures, the U.T.G. is easily calibrated to within thousandths of an inch.