These high-quality PHANO China Markers by Dixon Ticonderoga write very very smoothly. These specialized pencils and markers go by many names-- wax pencils, grease pencils, china markers. They provide solutions when you have to write or draw on a smooth surface (surfaces to which many other writing tools don't adhere) such as glass, metal, polished and natural stone, ceramics, plastic, tile and mylar. But unlike indelible markers and pens, you get a firm, clear mark that you can easily clean when you need. The markings rub off easily with a dry tissue or lint-free cotton wiper. To "sharpen", one needs only to unravel the wrapper. Marks remain readable to 175ºF.