Let me add generally the “900M tips compatible” is mentioned ad nauseam. The 900M series was discontinued by Hakko as far as I know, the T18 series is where to look at if looking for tips for the above mentioned irons (TS100 excluded).

Advice: don't waste your time buying cheap 10 piece packs of “900M” tips. Such tips are garbage and oxidize almost inmediately. Go genuine, it'll save you time, effort… and money.

:-)