http://www.rikenmt.com/products/cp36-waterproof-abrasive-paper.html Riken RMC CP36 sic sandpaper is a type of waterproof sandpaper. It can be used as wet and dry sanding. The C-weight paper base is a 30% latex paper imported from Europe. With Aluminum Oxide grains, Riken RMC CP36 could prevent curl very well. Features of CP36 Silicon Sandpaper Silicon carbide is a very hard mineral that cuts extremely fast. In fact, it is our fastest-cutting mineral abrasive. It features sharp points that fracture easily, resulting in freshly exposed sharp edges that produce a smooth, professional-looking finish. We use it in our silicon oxide sandpaper or sic abrasive paper. The mineral has a shorter life, but it produces a superior finish.