Genuine new 6 tooth speedo drive spindle that mated with 17 tooth speed pinion on cars with 10" wheels before 1980 plus any year 1275GT. Also 12"wheel cars with 3.44 final drive 1984 on. On the Metro mini this was used with 17 and 18 teeth pinions. Last of genuine new Rover items.most worms are from 20.20 worn up to 21.12mm wide.