Rigger turn fins

[HOTWATER]

Anyone out there know where I can buy a turn fin for an Avenger/ Spider/ Cobra OR a mongoose outrigger (for .21 size rigger)? I know this is an electric forum...but just thought I would throw this question out there. I know there's some "old school" guys out here for sure! Thanks so much!

[HOTWATER]

Here are some pics of my Avenger/ turn fin. This is basically the size and shape that I am looking for. Hope this helps...