I just bought a shift **** from ebay and it came with a pack of thread adapters that don't fit my 2001 mustang. The sizes were (8mm x 1.25, 10mm x 1.25, 12mm x 1.25 & 3/8" UNF). I contacted him and he said he would send me the right adapter if i would get back to him with a size. I know that it is 12mm but is there another measurement to be exact like: 12x? Thanks for the help in advance.

 

Measure the length of the threads and that is your second numeral(that is your length).You already have the width.