This 17 in. x 24 in. pressing mat from The Gypsy Quilter is 100% premium wool, a full 1/2 inch thick. Press any pieced or embroidered block with ease -- the density of this high-quality 100% felted wool mat absorbs seams and stitches, effectively pressing both sides at once. An added bonus? The texture of the wool stops fabrics from shifting, so there is no distortion when pressing. A handy tool for quick pressing when kept next to your sewing machine! You can also use this mat to block knitted projects by pinning them directly on it. This pressing mat can be used with a dry iron on most surfaces, but if using steam, place the mat on a protected surface since moisture does go through the mat and can harm the surface below. Safe surfaces include Formica, Corian, stone, and metal; wood and painted surfaces should be avoided. (Never place the mat on a rotary cutting mat when pressing; the heat could warp it.) If mat feels damp after use, hang to air-dry before storing. Wash the mat occasionally by rinsing it in cold water and hanging the mat until dry, especially if using a spray starch.