Notpolish's Sanding Band bit is a red coated carbide is designed to eliminate imperfections of acrylic and dip. Also, is gentle enough to use before application-like Gel. Perfect for smoothing out the natural nails or acrylic nails like a professional. Recommended to not let the Bit soak in acetone or barbicide longer than 10 minutes. Any time longer than suggested will result the Bit to discolor the red coat.