Y.S.PARK has developed an unprecedented tool, Head Fit Ruler for anyone to measure hair precisely. A "ruler for hair" can accurately measure the "length" and "angle" of hair. The pointed end fits the shape of the head to measure an angle of 90 degrees precisely. This product digitizes the accuracy that has been cultivated as an individual sensation, which enables the third person to check whether or not the haircut was done accurately with this tool. It is important to pass the skills on to the next generation and this product will assist the education for it. Ideal for education or demonstration at academies or salons.