The "rust eraser" isn't a sharpener, but it's useful in restoring your knife in the event of tarnish or rust. It's somewhat abrasive, and will leave a satin finish. It's quite effective in removing light rust and tarnish, but not deep pitting. They are about 3 1/8" long, 1" wide, and 5/8" thick. Current stock is from Lansky.