1Color Changing: When your nails come into contact with a warm or cold surface, the color of the nail polish changes, resulting in a fascinating gradient effect. Long nails are more noticeable. 2Smooth Application: The nail polish pen has a rotating device that dispenses gel nail polish and ensures smooth and even application 3Long Lasting: The premium formula ensures that the colors stay vibrant and fresh on your nails for an extended period, does not fall off or fade. 4DIY Nail Art: Highly sensitive to temperature, gel nail polish pens are perfect for creating unique and eye catching nail designs, making them the perfect choice for nail lovers to enjoy DIY nail art. 5Important Note: Clean and polish the nail surface before use, in rare cases, gel polishes may cause an allergic reaction to skin contact. Test before use.