If you are racing or traveling at high - speeds through the desert for sustained durations your shocks are going to heat up significantly as they absorb the energy of the constant pounding. OE shock seals are designed to work in below freezing temperatures and up to the heat of generated by normal vehicle usage, but when you race or run at a high constant speed you can push OE seals out of their optimal operating zone. FOX high temperature packs contain high temppressure oil seals and high temp Viton fluorocarbon o - rings for the internal floating piston (IFP) for better performance and longer service intervals in extreme heat conditions.