System1 Designs 2.25" Inch Black Silicone High Temperature Straight Coupler 3 Layers of Polyester Reinforcement Suitable Soft Hose Turbo Intercooler Pipe System1 Designs line of silicone couplers feature 3 layers of polyester reinforcement and are suitable for applications with boost pressures up to 45psi. They also feature a temperature rating of 428ï°F for direct to turbocharger installations. Features: Length: 3" Material: 3-ply Polyester Reinforced Temp: 428 Degrees F (220 C) System1 Designs line of silicone couplers feature 3 layers of polyester reinforcement and are suitable for applications with boost pressures up to 45psi. They also feature a temperature rating of 428ï°F for direct to turbocharger installations.