Natural Sea Sponge is great for a bath sponge. Natural Sea Sponges can be used for a multitude of things The 4" Natural Sea Sponge Bath is the ideal size of all Natural Bath Sea Sponge. - The Mar-Dee 4 inch sea wool sponge is rated 9 out of 10 for softness - The Mar-Dee sea wool sponge is ranked 10 out of 10 for durability. - Harvested from the cost of Florida and the Caribbean. - A natural sponge reproduces itself after harvesting. - Inhibits bacteria, mold, and mildew.