For makeup sponge, there are different kinds of material. Generally, there are NR, SBR, NBR, PU, rubycell. For NR, SBR, NBR, generally we call them latex sponge. For PU, we call it latex free sponge, its full name is Polyurethane.
For NR, SBR, NBR, what kinds of makeup sponge will use it? it is frequently used in the flat makeup sponge. When it is put in the water, it will not become larger.
For PU sponge, it is used in the beauty sponge(3D makeup sponge), when it is in the water, it can become larger.
For rubycell material, it is used in the air cushion puff.
For the price, NBR>SBR>NR， NBR price is alomost equal to Rubycell material. For PU, its price is almost equal to SBR price.
From the environmentally friendly and good to the skin, PU is the mostly used among all these different sponge material.