Half Square Triangles Tool?

The only ruler I would buy is the June Tailor Half Square Triangle ruler. You will get absolutely perfect HST with it. It has two slits in which you place you marking pen to draw the SEWING lines, not cutting lines. After you sew it, it has another slit to place your rotary cutter in to cut them in half. (I just use my scissors for this.) The most important part is the center part where you square up your HST to perfection. Be sure to read how to place the ruler for squaring. You can make HST from 1.5 inches to 6.5 inches, and perfect all the time. Search for a YouTube video to see it in action.