Specifically-engineered materials resist collapse under vacuum Engineered to resist electrochemical degradation – the leading cause of hose failure EPDM tube; synthetic fiber knit reinforcement, heat-, ozone- and chemical coolant-resistant EPDM cover Manufactured with OEM-exact hose components (quick connects, branch connectors/tees, sensors, etc.) Meets SAE 20R3 EC Class D1 under 25mm (1 in.) ID, SAE 20R4 EC Class D1 for 25mm (1 in.) ID and over