The sponge holder has 4 holes for the screws and for holes in the front for an easy pass of the screwdriver.
The base of the sponge holder has the role to assicure the airflow under the sponge and avoid stagnation of water and formation of mold.
The cloth holder has a differet shape of the arms from the picture but the results is the same.
My advice is to print this models in PETG, because PLA is biodegradable and it doesn't like humidy place.
Enjoy it ;)
The author hasn't provided the model origin yet.