[RELIABLE MATERIAL]: The point of the art ruling pen is made of iron, enough for long time use, the pen-holder is made of high quality plastic, and comforable for fine line drawing. [ADJUSTABLE PENS ]: You can control width by adjusting screws, tightening or loosening them to draw right line, loosen the screws after use to avoid deformation of pen. [EASY TO USE ]: Dip the ink in the space when using. If you want to draw a straight line, the pen must be perpendicular to the paper and draw a horizontal line with even force. [WIDE APPLICATION]: Suitable for fine line drawing, technical drawing, cartography and calligraphy, a perfect tool for both beginners and artists to draw and paint. The nib is covered with wax to prevent rust and sharp danger. High temperature may melt and redness. It is not rusty. It can be wiped off with a damp cloth. Colour: green + black Material: metal + plastic Package Contents: 1 * 4.8 inch pen (black) 1 * 5 inch pen (black) 1 * 5.3 inch pen (black) 1 * 6 inch pen (black) 1 * wide mouth pen (green) Only the above package content, other products are not included. Note: Light 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.