Buy 4 and only pay for 3 Bristle type: Synthetic What it is: Slanted buffing brush that allows for even pressure and distribution of product across the face. What it does: Features a sculpted shape that conforms to the unique curves and contours of your face. Its smaller head size nestles perfectly into the under eye area, and also concentrates coverage over blemishes and spots on the face. The rounded synthetic bristles give you a full-coverage, seamless finish that works with all formulas.