This is a sponge holder specifically for the Sctoch-Brite Sponge handle. This will hold it on the sink.
spongeholder = will require a suction cup on the bottom https://www.homedepot.com/p/OOK-5-lb-Clear-Plastic-Suction-Cup-Hooks-3-Pack-54404/202341596
spongeholder2 = Updated version that works with 18mm X 3mm neodymium magnets. Much easier to use on the sink, place one under the sink and one in the model to make it work.
spongeholder2bigger = Same as spongeholder2 but made the opening 5mm wider to fit the sponge more easily.
Would recommend to print spongeholder2bigger
The author hasn't provided the model origin yet.