The plant sponges are in fact the fruit of a vine type plant called Luffa. The fruit has a cucumber-like shape and is even edible in some Asian countries, if harvested when the fruit is still young.
The plant is usually grown in temperate to warm climates, and is a very strong, rustic plant, so you can have it in your own garden if you wish. If you let the fruit ripen on the plant, you will find inside its shell that the fiber has dried and acquired a texture similar to that of a bath sponge. You can also buy them in health food stores or street markets.
Koronis Venice sponge is a natural plant sponge, it can be used for the whole family. Try it and you will feel the benefits on your skin!