This lapping film is 100% made in the USA by 3M. These micro-finishing sheets have been developed for industrial applications and can be used to flatten or polish just about anything. This lapping film contains carefully graded aluminium oxide particles that are electrostatically coated on a backing made of high strength polyester film. This fast cut, water resistant abrasive offers precise, consistent and narrow tolerance finishes and is available in a wide range of precise micron grades to meet any need for sharpening or polishing. They can be fixed to a flat, hard surface (usually 1/4" glass) and used to get a scary sharp edge on wood chisels or planing irons. They can be wrapped around contoured sticks and used to sharpen carving tools. They can put a sharp edge on all types of knives. They can also be used to polish jewelry or gemstones. They are PSA and have pressure sensitive support. They have a 3mm high strength polyester film backing which is less likely to tear than traditional wet or dry sandpaper. Leaves are not marked, so using their color is the only accurate way to identify them. These aluminum oxide (AO) sheets are available in the following grades: 1) 0.3 micron (white) or 60,000 grit 2) 1 micron (light green) or 14000 grit 3) 3 micron (pink) or 8000 grit 4) 9 micron (light blue) or grit 1800 5) 12 microns (yellow). or 120 Grit 0 6) 30 micron (green) or 600 and 7 grit) 40 micron (blue) or 300 grit. Leaves are not marked, so using their color is the only accurate way to identify. In finer grains, it can be difficult to differentiate the abrasive side of the substrate. The abrasive side will always have a matte finish, where the back side of the film will be glossy.