[Hoop]

Would recommend not buying stuff you don't need, especially tools. If you don't need a dial back, don't buy one.

If you are buying a timing light only to set your initial advance of 2 or 4 degrees, I don't think you need a dial back.

If you want to know the rpm at which full advance, like 26 degrees, comes in, that's a different need.

Know what you're buying and why. There are plenty of videos on the internet that demonstrate how to use a dial timing light ... and why.