If you're doing a timing belt change on your Honda/Acura V6, you'll need this part to hold the pulley in place with a breaker bar while you try and muscle the bolt off, and then you can use it to rotate the crank shaft to get the timing marks aligned as you put the new bolt on. In my case the dealership wanted to charge me $1200 for the timing belt service, so I didn't feel too bad about splurging for this tool. It did the job!