CRUSHPROOF Oval Adapter measures 3" x 6" and fits twin tailpipes up to 2" with a maximum oval size of 2.5" x 5.5", adapting to 3" and 4" ID CRUSHPROOF hose. CRUSHPROOF tailpipe adapters are designed to protect the hose and tailpipe, and dynamometer hoses and adapters are formulated to withstand the high temperature of a dynamometer, with a heavy wall thickness that increases durability. Always select an adapter with at least 1/2" diameter clearance around the tailpipe.