Stud, special Step down, 8mm x 1.25 on one end and 6mm x 1.0 on other end. Short section of very standard 8mm x 1.25 pitch thread and short shank, the 6mm threads.

ex. use for adapting smaller hole drain flanges onto drain flange bolt pattern on Garrett GTBB turbos. (1) stud and (1)6mm nut included.