source for plastic buckles?

[GanzAndere]

i'm rigging my new kayak seat (surf to summit GTS elite) and need to buy a couple of plastic buckles. any ideas if there's a local store that sells these?

found some online sources, but wish i knew where i could just walk in and buy 2 locally. gotta figure exactly what size i need -- but that would be simple to figure out if i could just bring in one i need to match.

i'm in the triangle area. checked at REI today (near southpoint mall/durham), and they didn't carry them.

photo attached.

thanks for any leads.

// joel