Special grinding wheel for Pfaff and Durkopp knives No. 119202 and 119444, diameter 100 mm, width 3 mm. Suitable for models 68/1, 82-100 (left side). Hardness: H, grit: 100. Hardness is designated by a letter. The farther the letter progresses in the alphabetical sequence, the harder is the condition of the grinding wheel. Grit is designated by a number. The higher the number, the finer the condition of the grinding wheel.