hi, It's the sleeve that connects the RESONATOR, Turbo to the HOSE, Charge Air which is a aluminum pipe off the turbo... It has a rubber sleeve about 2 in. id and 2.25 od about 2.5 in long. On the truck I'am working on keeps pushing the sleeve out , which puts a underboost code 0299..I've been the dodge and guess what? they only show an o'ring..wrong wrong.. any help would be appreciated