this thing is great. It's clear plastic so can't break it, but I got about 4 of these recently. They are of great importance in my craft, especially card making. You don't have to measure three times and make small marks to align a straight line. The T-square hooks to the side of the card, forming a 90 degree angle. and voila, you have a straight line. I just use a ruler to line up the stamps with the letters so they are straight, I don't even have to draw a line. I would give it 5 stars except that it doesn't break. I could have given 4 Β½ stars. I never had a single break.