CRUSHPROOF Dyno Y-Assembly is designed for twin exhaust pipes on new diesel pick-up trucks, consisting of a 4" x 11' ACT400 DYNO hose, an AY40 Y-Connector, and two (2) F475DYNO Oval Tailpipe Adapters. The DYNO hose will take the heat, while the adapters allow for more air flow. CRUSHPROOF Y-assemblies are designed for converting a single hose into two hoses for dual exhaust vehicles, and this product can also be connected to a standard black hose. This hose must be used with a fan-assisted system and will not work during the regeneration cycle, but it is great for use on ALL dual exhaust vehicles!