quad sup fins

Try this
www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/Quad-Fins-2/?SearchTerms=Quad,sup,fins

and the search tool should give you plenty of info.

(For future boxes) Simon Anderson SA'4 are a pretty safe bet or the Gerry Lopez Quads for larger boards like yours. IMHO . I was a quad junkie but have since switched to the New Jamie Mitchell 2+1's

I like the Futures Controller quad set. Pricey but worth the money.