Description from Garrett Wade
These 3-1/4 x 2 x 3/4″ blocks are made from a special rubber compound saturated with silicon carbide particles. They work on metal the way an eraser works on paper. They will not clog up or load, and can be cut with a utility knife to fit any shape. Can be used dry or with any standard lubricant, including water.
The coarse block is superb for cleaning any metal surface, and the fine block is great for polishing. The medium block works for in-between situations. Polish your machinery tables for extra slickness; clean rust, corrosion, scratches or stains from virtually any metal surface. Get all three and save.
Made in Germany.