CRUSHPROOF Oval Adapter measures 3.5" x 8.5" and fits twin tailpipes up to 3" with a maximum oval size of 3" x 8", adapting to 3" and 4" ID CRUSHPROOF hose. CRUSHPROOF tailpipe adapters are designed to protect the hose and tailpipe, and the hook and chain holds them in place. Always select an adapter with at least 1/2" diameter clearance around the tailpipe.