This are splitfins compatible with mini figures.
The fins has a realistic angled blade, so it is NOT possible to stand with this fins. For splitfins which allowed the Minifig to stand look here:
Minifig Splitfin without blade angle
This fins has a split like modern splitfins.
The set contains one pair (two single fins).
Successful printed in FUD and Royal Blue Strong & Flexible Polished.