Fcs sf4

hi all, so i brought a sweet potato and i have a set of 4 fins for it- they are the 2 sizes- small at the back and have SF4 written on them, so are these the stretch fins which people go on about?

when i do a good search i do get the same pics but also i see yellow stretches and ones with the word stretch on them? my fins are plane but with SF4

cheers, james

Same template, different materials and branding is available.

thanks mate, am loving the board, it does catch waves easily, now just learning to ride it and progress.