This item is used on multiple models.
THIS ITEM IS NEW OLD STOCK - BRASS MAY SHOW SIGNS OF AGE FROM OXIDATION.
Can be cleaned with Brasso or similar brass cleaning product if desired, but spotting is generally only cosmetic.
Regarding the Fathom SD reels: FTHSD12, FTHSD15, FTHSD25N, FTHSD30, FTHSD40
The #12 yoke and #12A yoke bushings were changed sometime after the first release.
The later yoke is stainless, slightly thicker, with smaller screw holes. The thicker yoke fits better in the #13-FTHSD12 pinion gear, with less slop when shifting into gear.
The easiest way to identify is the material, as the older yoke was brass.
If changing older to newer yoke, make sure to change the bushings as well.