Micro-Perf 40 Tooth Paper With 30-, 40- and 50-tooth rules, Micro-Perf is ideal for perforating continuous-feed forms, creating a perforation line that remains clean with no stray fibers or rough edges. The rules are available in a rule height of .022 up to .029 inch, designed for use on paper or card stocks. Micro-Perf is also ideal for jobs that will be passed through a laser printer after being perforated.