I need the replacement nut (star knob) to adjust and hold the seat in place on my Riot whitewater kayak.

I need the replacement nut (star knob) to adjust and hold the seat in place on my Riot whitewater kayak.

HI

You will need this part.  SKU 21003

https://boutiqueborealdesign.com/products/umat-109-knob-m6-female-25mm-deep-black-nylon-with-brass-insert

Hope this helps,