How fast is your tennis serve? Can you hit a 150 mph serve or a clumsy 20-mph?What is the highest speed of your fastest ace?Can you beat the best serves in the world?This is the one and only app that can measure the speed of your serve. It is perfectly accurate. It also lets you bounce the tennis ball before serving.Challenge your friends. It draws a crowd at parties and bars.It is both a fun game and a tool. It gives you the speed of your serve in miles/hour or km/hour and the fastest serves ever.Practice and track your progress.Serve as fast and skillfully as you can, but hold on tight to your iPhone though.