A holder for the world famous Weller sponge.
Still works better than the Brass turnings.
I have a JBC soldering iron at work (super!) but I miss my Weller sponge :-)
I made one with my name on it, yours is without the vanity stuff of course.
You can buy the sponge here.
Sponge: search for T0052242099
https://www.distrelec.nl/nl/replacement-sponge-weller-t0052242099/p/18248398
or
or
https://nl.farnell.com/weller/t0052242099/sponge-double-layer-70x55x16mm/dp/2249942
The author hasn't provided the model origin yet.