Notpolish Under Nail Cleaner bit is a red coated carbide it is an essential for you! Designed to save time when prepping. Remove the excess, dirt and dust. Get in between those hard surfaces in a safe way-under and over the nails-plus cuticles! The drill bit is gentle and will not damage the natural nails and skin. 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.