Precision 20^o pressure angle plastic racks from Quality Transmission Components are stocked in 13 sizes in pitch size modules 1~3. These hobbed racks, identified as the PR, and PRF Series, are made of MC901 and have a tooth hardness of 115~120HRR. They conform to KHK R 001 grade 5 standards. Total rack lengths range from 505 mm to 1010 mm. Face widths range from 10 mm to 30 mm. Rack heights range from 12 mm to 35 mm.