This is a cable winder to clip on the prongs of a europlug. It is designed in a way you can use it without unwinding the whole cable, while being space efficient for storage.

It has diameter-staggered cable clips, I use one for the initial winding and one for the final securing of the cable.

It is not compatible with Schuko plugs (prong diameter) and should not be used with thick cables, since the bend radius is probably too small.