These marker refill ink have 3 colors,quick-drying and rubbing resistance,no fading and durable Portable ink filling bottle mouth,filling to prevent waste,more economical When the ink is run out,let the marker pens can be reused to avoid waste.Sealed design,the ink is volatile and the needs to be tightened after use Can write on any solid,waterproof and quick-drying,ready to write,the color is bright Oil-based ink is suitable for most marker pens,poster pens,etc.Practical and convenient