Wetordry 32038Click To Copy Sandpaper, 9 in W x 11 in L, 400 Grit, Aluminum Oxide Abrasive, Black, Wet/Dry

Wet sanding and dry sanding each have their own advantages for sanding effectiveness, time savings and creating a professional-grade finish for your auto body repairs. Wet sanding helps keep dust out of the air and reduces clogging of the sandpaper which can slow you down and cause unwanted scratches in the surface. Wet sanding is generally done during the more refined stages of body repair. Dry sanding tend to remove stock from the surface faster and saves you from having to continually dry the surface - you can instantly check the progress of your work. Our 3M™ Wetordry™ sandpaper saves you time and hassle right from the start. It allows you to keep just one sandpaper on hand and to eliminate extra time switching between sandpapers, even if your project requires both dry and wet sanding.
3M Wetordry sandpaper uses A/O aluminum oxide AO as the abrasive material. 3M incorporates this A/O aluminum oxide AO material into the sandpaper forming a grit of 400. The sandpaper has a width of 9 in and length of 11 in. This abrasive is on a paper backing, A weight.
Specification parameters description:

Backing Weight:
Paper and cloth have a lettering scale for backing weight that measures strength of the material onto which the abrasive is mounted. Paper uses the letters A-F, where A is a lighter weight and most flexible and F represents a rigid, heavier backing. Lighter backings are typically paired with finer abrasive grits, suitable for blending and finishing. Coarser grits used for deburring and stock removal rely on a heavier backing. Cloth uses a lettering system of J, X, and Y for backing weight. J weight (jeans) is the lightest and most flexible, X weight (drills) is more durable and recommended for medium duty work, and Y weight is the toughest and least flexible. Fiber backings are made from chemically-impregnated paper to form a very hard, strong backing material. Fiber is used primarily for sanding discs. Polyester film backing provides high strength with a very thin backing and is used for very fine grits. It is more tear resistant than paper backing and is also waterproof.
Grade:
Grade is a measurement of the size of abrasive particles embedded in coated abrasives. It is a more general measurement of the level of precision, and corresponds roughly to grit. A smaller grit number means larger particles and a coarser grade, while high number grits are used for finer work.
Grit:
Grit is a measurement of the size of abrasive particles embedded in coated abrasives. The most common standards for grit size are the United States CAMI (Coated Abrasive Manufacturers Institute) and the European FEPA (Federation of European Producers of Abrasives). A smaller grit number means larger particles and a coarser grade, while high number grits are used for finer work. Grit is generally a unitless measure but is sometimes measured in microns.