Material: Tempered GlassR-Stick is a tempered glass file that can easily and easily handle narrow and concave curved parts of plastic models.The tip on one side has a conical shape, making it ideal for widening the mold and trimming after carving.*How to useDo not put too much force on the file, and if you gently stroke it, the finish will be beautiful and you can prevent the file from being damaged.If the glass file becomes clogged, you can wash it with water. If the clogging is severe, you can remove the clogging by gently rubbing it with a brush and washing it with water.