I have never seen tools for this before, where I started working, an older fellow had a set made of bent wire, done by himself. These were for re-setting the odometer on used cars. yes, rolling back the numbers, to make that used 100,000 mile car a little sweeter to sell. In the 60s, a Cadillac dealer completely detailed each used Caddy, made her shine, then rolled back the odometer to 29,000 miles. So every used Caddy on the lot had less than 30,000 on it. Oh, the feds made this all illegal in the early 70s, hefty fines, I know one man that got a brand new pickup from his dealer, when he found out the odometer wasn't right! Had to love the old days, John