Hi!
These are pool floaties I designed to be used with Lego minifigures. The floaties goes in between their legs and torsos.
I made these for a Lego water park moc
I used a model for a Lego utility belt by neilmac on thingiverse ( https://www.thingiverse.com/thing:2237136) for the shape of the holes in the floats
The author remixed this model.