This is an aluminum ruler suitable for stained glass making and other similar crafts. It's easy to use, with a comfortable weight and shape that fits well in the hand. The top and sides are made of a material that allows a glass cutter to slide smoothly, while the back is made of a non-slip material that fits the glass. While a regular cutter can also be used, please be aware that the blade will scratch the ruler. Effective length: approximately 24.2cm Width: approximately 6cm Although there are almost no scratches, please be aware of any minor scratches. There are no scratches that would interfere with your work. Thank you for your understanding. Thank you.