Hi Derek, I'm glad to assist you. The diameter is not noted anymore since this is a direct-fit vehicle-specific part. Simply by providing or choosing the correct vehicle application, the guaranteed fit badge (round green badge with a white checkmark) would confirm fitment. Grab our discounted sale price offer (34% less already) and click the link below to order today. Happy shopping! https://www.carparts.com/catalytic-converter/evan-fischer/repm960321?can=CPJE1043_20220626

Hello John, This part has the flex pipe on the other end. To check the fitment please use our Vehicle Selector — which can be found towards the top of the homepage as well as all category, search results, and product pages — can help verify if a part will fit your specific application. To enter your application, simply select your vehicle’s year, make, model, sub-model, and engine type and click “Go.” Once your application is selected, you’ll see a “Guaranteed to Fit” badge if the part will fit, and we recommend that you also double-check Your Vehicle Fit Details as well as the Vehicle Fitment Information table on the product page.