PPE's Silicone Hoses are constructed using Fluorocarbon lined, silicon rubber that is strengthened with five plies of Nomex fibers. This design results in a hose that resists fuel, oil, UV, ozone, as well as various other chemicals, plus it has a burst rating of over 200 psi from negative 76 degrees to 437 degrees Fahrenheit. Simply put, these will be the last hoses and boots you will ever buy.