Lansky Eraser Block to Remove Rust & Stain Use to remove rust and stain on knife and other metal object. Also can be used to clean ceramic honing rod. Dimension: 8.2 cm X 2.5 cm X 1.6 cm CAUTION: On highly polished or reflective surfaces, this eraser block may cause dulling and leave a brushed satin appearance. Made by Lansky, a company specialized in knife sharpening.