This set contains a single sheet of 5/16 x 5 x 12 dead flat float glass and 7 sheets of lapping film 4-1/4 x 11 in the following microns sizes .3. 1,3,5,12,30 and 40 5/16 Float glass is dead flat and the perfect substrate to attach abrasive sheets Float glass will accommodate a half sheet of lapping film Lapping film has Pressure Sensitive Adhesive (PSA) backing with 3 mil high-strength polyester film backing to minimize tearing The Scary Sharp Sharpening Method is an approach to sharpening knives and woodworking tools that is fast, effective, consistent and very cost effective. This is a Scary Sharp Sharpening kit with one sheet 5/16 inch float glass and 7 sheets microfinishing film. The Scary Sharp Sharpening Method is an approach to sharpening edge tools that is fast, effective, consistent and very cost effective. Instead of using conventional, more expensive and messy oil, water or diamond stones, the Scary Sharp Method uses specialized microfinishing or lapping film that is adhered to hard, flat substrates. High quality Aluminum Oxide, Silicon Carbide or Diamond films can be procured for a reasonable cost per sheet. Float glass is considered the preferred substrate as it is “dead flat”. Pressure Sensitive Adhesive (PSA) sheets are recommended as they can be easily applied to glass or granite. Fresh lapping film will cut faster than most sharpening stones and is easily and quickly replaced when dull. Unlike traditional water or oil stones, no maintenance is required since the glass will not hollow from prolonged use. The Scary Sharp Method will quickly sharpen any knife or cutting tool with excellent and consistent results. This lapping film has a 3 mil high-strength polyester film backing which is less likely to tear than traditional wet or dry sandpaper. This lapping film also has pressure sensitive adhesive (PSA) backing. The sheets are not marked so using their color is the only accurate way to identify them. Grades are as follows: 1) 0.3 micron (white) or 60.000 grit 2) 1 micron (light green) or 14,000 grit 3) 3 micron (pink) or 8,000 grit 4) 9 micron (light blue) or 1800 grit 5) 12 micron (yellow) or 1200 grit 6) 30 micron (green) or 600 grit and 7) 40 micron (blue) or 300 grit. In the finer grits, it can be difficult to differentiate the abrasive side from the backing. The abrasive side will always have a matte finish, where the film backing side will be glossy.