IMPERIAL 01853 740I Series Dust Free Abrasive Disc, 8 in Dia, 36 Grit, Hook and Loop, Purple

The 740I Hookit™ abrasive disc is a heavy E weight paper disc built for long life and high performance during auto body jobs such as deburring, shaping and the removal of rust and paint. It is resin bonded to resist heat and a self-fracturing aluminum oxide cutting surface stays sharper longer than standard abrasives. Grades include 36E, 40E and 60E for the toughest applications.
3M Imperial Hookit coated hook & loop disc uses ceramic as the abrasive material and has a diameter of 8 in. 3M incorporates this ceramic material into the hook & loop disc forming a grit of 36. This abrasive is on a paper backing, E weight.
Specifications:

Abrasive Type: Coated

Specification parameters description:

Abrasive Material:
Values: A/O Aluminum Oxide AO A/Z Alumina Zirconia AZ S/C Silicon Carbide SC Aluminum Oxide Aluminum oxide is an artificial abrasive suited for general purpose stock removal and finishing. It is the mostly commonly used abrasive and can be used for most steels and ferrous alloys. Aluminum oxide is slightly softer but tougher than silicon carbide. Ceramic Ceramic is used for aggressive cutting and grinding of stainless steel, titanium, and metal alloys. The abrasive grain is designed to fracture during use so that it maintains sharpness. Ceramic Aluminum Oxide Cerium Oxide Cerium oxide is used for fine polishing and lapping of glass, gemstones, optical mirrors, and lenses. It should be used wet or in slurry form. Diamond Diamond can be either natural or manufactured and is one of the hardest abrasive materials. It is commonly used for grinding and polishing stone and very hard steels, and for sharpening other cutting tools. Nylon Silicon Carbide Silicon carbide is a manufactured material that is extremely hard but brittle. It is commonly used for fast cutting under light pressure, particularly on cast iron, nonferrous metals, and materials such as glass and plastic. Precision Shaped Ceramic Grain Zirconia
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.
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.
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.