Finally there is an app that tells you the appropriate fiberoptic scope for the endotracheal, double lumen tube or blocker that you want to use. Just select the ETT you want and the app will give you the maximum fiberoptic scope that will fit through. You can use that size or the next size smaller. This app takes all the uncertainty out of a possible emergent situation, and it does it with just one touch. Don't fumble around sticking the scope through all those tubes just to find the right one. Get your answer, fast!