A two-sided sponge brush typically refers to a styling tool with different textures on each side, designed for creating various hairstyles, particularly for curly or textured hair. One side often features a multi-hole or wave pattern for defining curls and waves, while the other side might have a different texture (like a smoother surface or a different hole pattern) for adding volume or texture. They are generally made of soft, flexible sponge material to minimize damage and breakage during styling.