ok I just have to say the slotted rulers are my absolute favorite! The trick - at least for me - was to make sure I fold and iron the fabric to the correct size for the ruler (measure from the bottom of the teardrop opening of the slots - to the same on the other end). I have successfully done strips of all widths in no time and also do squares all the time by removing the ruler and turning my mat 90 degrees and making the juxtaposing slot cuts. I truly could not live without this ruler because I can't really afford pre-cuts.