PUR uses a much thinner application of adhesive than compared with EVA (10 to 12ml vs. 25 to 35ml per EVA). This thinner application of adhesive, along with its reactive properties, is what gives PUR its flexibility. In testing, PUR has extremely high flex-test values, often in excess of 1,000 flexes. It is this flexibility that allows also for greater lay-flat characteristics. When applied properly, PUR’s lay-flat ability is comparable to that of true Otabind. Additionally, a thinner application frequently will improve performance and result in improved “mileage” over time. With less adhesive on the spine, there is less distortion of shape and cleaner overall appearance.