This thinfire paper is the ideal size to use in microwave kilns, each piece is 10cm x 10cm. You can choose a pack of 10 or 25 pieces. This thinfire shelf paper produces a lovely smooth finish on the bottom of your kiln-fired projects. It is much quicker and easier to use than shelf primer. The Bullseye logo is printed on the bottom side. The paper can be used the opposite way up if you want a rougher finish to the bottom of your work. Each sheet is good for one use only.