I need a thigh brace for the Riot Enduro kayak.

If you have a newer model of the Riot Enduro with the Flex 4 Seat the thigh brace for it is:

https://boutiqueborealdesign.com/products/thighbraces-for-flex-system

If you have an older style (no Flex 4 - older style seat), then the thigh brace for that is:

https://boutiqueborealdesign.com/products/bd-thighbrace-2-pcs

Hope this helps,