How to use: These refillable pens are designed for easy operation. Simply remove the nib area, insert the steel ball, fill with your desired paint or ink, and reinstall the nib. The transparent pen body allows you to easily monitor the ink level. (Be careful not to pull out the refill, otherwise it may affect the use) How to add ink: If you add marker ink, whiteboard water, alcohol, or water-based ink to the pen tube, please gently the nib to prevent backflow, otherwise the ink spit out and not flow back into the pen tube; when adding acrylic pigment ink, powder ink, or paint ink, you need powder particles above 800 mesh or reach the nanometer standard to write the color, otherwise the ink flow out from both sides. Versatile paint touch-up pen: Our refillable acrylic marker pen set contains 23 pieces with round, tilted, and flat nibs, suitable for a variety of art projects, graffiti, and handicrafts. Can be easily filled with acrylic, oil painting, watercolor, or ink of . High-quality materials: These pens are made of plastic with a polyester nib and internal steel ball to smooth writing and prevent ink from solidifying. Enjoy long-lasting performance and reliable results with every use. Wide Application: These refillable pens are perfect for home, school, or painting classes and can be used on a variety of surfaces such as canvas, paper, glass, etc. Perfect for students, artists, and hobbyists to explore their creativity. Weight: 350g Product size: see engineering drawing Color: As Shown Material: plastic Package Contents: 8pcs * 3mm pen 8pcs * 6mm pen 4pcs * 15mm pen 3pcs * 3 ml Dropper Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.