I have used this circular saw guide for years and it has saved so much time. At about $15 it is a no-brainer. If you build decks or do a lot of cross-cuts you will love this simple tool.
Basically the first time you use the tool you cut through the guide itself with your saw snug against the left fence. You have just customized the guide to show you exactly where that saw blade will cut – because you just cut through it at that point! Genius!
Just make your measurement and then place the Pro-Cut on your mark ensuring perfect right angle cuts every time. Easier to use than describe!