In addition to this protractor I now own quite a collection of Incra rules in different sizes and configurations (straight, T, bend, protractors). All of them are based on the 0.5mm pencil marking holes and slots. I cant imagine going back to standard rules and gauges and expecting a level of precision and accuracy that you can get with the Incra rules. Whoever thought this idea up, and then went to the trouble to commercialize the idea, is quite simply a genius. I should probably say a genius that spent a lot of time and frustration and rework measuring and marking with conventional rules. When you consider the benefit Incra rules provide youll quickly realize the price is a bargain.