The Diane Fan Mask Brush is a fan-shaped brush made with 100% boar bristle, used to apply facial masks and similar treatments evenly across the skin. The wide, flat fan shape spreads product in a thin layer rather than the thicker, more concentrated application you'd get from a round or paddle brush.
Boar bristle is a natural fibre commonly used in skincare application brushes because it holds and releases cream or clay-based product smoothly without absorbing too much of it, and its firm-but-flexible feel allows even, controlled strokes across the face. This style of brush is a standard tool in spas, esthetician studios, and skincare-focused salons for mask and treatment application.