G2 to G4 Glass Fiber Media Rolls -The density of the fiber from entry to exit is from lower to higher, this makes deep filtration realized. -High temperature resistant: up to 150 degree C. -Humidityï¼?100% RH 3. Applications of G2 to G4 Glass Fiber Media Rolls Special used as a pre filter for paint/oil mist filtration in exhaust system, such as spray booth, high humidity air filtration system.