In the evaluation of vascular grafts and/or products that go into the vasculature, Dynatek was the first to realize that one of the most important mechanical characteristics is the dynamic internal compliance. Previously, only external measurements were taken and often were acquired in a static mode. After a thorough literature search and years of research, Dynatek not only demonstrated the errors inherent in external measurements, particularly of a static nature, but designed instruments and protocols to evaluate this critically important characteristic.