This Y pipe fits Tundra, 5.7L V8 2007-2009 Double Cab and Crew Cab trucks. It does not fit the Regular Cab.
This Y pipe is designed to bolt to the rear of the Doug Thorley Long Tube headers and completely replaces the pipe containing the two catalytic converters and bolts to rest of the exhaust system.
This prevents you from having to cut the front cat from the cat pipe when installing the Doug Thorley long tube headers and making the installation a complete bolt on installation that is easily reversible when needed.