Exhibiting strength and clarity while reducing or eliminating stress cracking at interface with flexible PVC components, Apex SCR™ heat-stable compounds enable rigid PVC to replace polycarbonate (PC) in such clear medical components as connectors and check valves. It took Apex SCR rigid PVC grades 1–2½ weeks or more to exhibit stress cracking during testing. Simultaneously, compounds exhibited required toughness, rigidity, and clarity suited for typical applications.