Norton ProSand Premium Job Pack Abrasive Sheet, Next Generation of 3X Technology, Fiber Backing, Aluminum Oxide, Grit P320 20 Sheets The NORTON IM9 India fine-grit replacement oilstone for the IM313 sharpening system is made of 320-grit aluminum oxide, suitable for sharpening and maintaining steel cutting edges; it produces durable, smooth-cutting edges and is preferred for close tolerances. The stone is prefilled with oil to save time and eliminate the need to presoak it prior to use. The oil prevents metal from bonding with the abrasive surface by flushing away dislodged abrasive and metal chips. This oilstone is commonly used to replace a stone in the Norton IM313 sharpening system, or as a bench stone, to restore cutting edges on straight-edged tools such as chisels, knives, plane blades, and precision instruments. Features Load resistant stearate coating, fiber reinforced backing, and high quality zirconia alumina combine to give 3X the performance of typical aluminum oxide paper sheets Zirconia alumina is self-sharpening and durable, allowing for a faster cut rate than aluminum oxide Open-coat construction offers more flexibility and clog resistance than a closed-coat sheet Water-based stearate coating resists loading for extended abrasive life Paper backing is flexible, and offers a more consistent finish than a cloth or fiber backing, while being thicker and more durable than a polyester film backing USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.