If you want to check with Jantz at DAVIS, OK. ,1-800-351-8900 Their checkering file is 20/ inch item GNCF00 IS 24.95 30/INCH IS GNCFO IS 24.95 and their 40/inch is GNCF1 IS 26.95 WITH SHIPPING ADDED IS 8.95. I have used their 20/inch for over 15years and always good items and even when I used it on hardened steel stood up way longer than I thought possible. Mike