Premium Material: Made of good-quality sponge, felt and plastic, washable and reusable. The black tip is made of sponge and the white tip is made of felt, helping smoothly blend different sides. The plastic pole makes them comfortable to hold. Size Information: The thick blending pen measures 15x1.2cm/5.90x0.47 inch and the thin blending pen measures 14x0.75cm/5.51x0.29 inch respectively. Double-Headed Design: The black tip of larger pen is for shadow-side transition, and the white tip is for transitioning halftones into light and dark sides or blending light sides; the black tip of smaller pen is for details handling, making your sketch more dynamic and visually appealing. Package Content: You receive 4 pieces of blending pens. Sufficient quantity to meet your use in art classes, and it's an useful addition to your . The white felt tip may contain some black wool but it doesn't affect the actual use. Wide Usage: This blending sponge pen set is suitable for most occasions, such as art works, school assignments or , and is a practical tool for students, beginners and art lovers, helping you easily blend and color and creating beautiful gradients and shading in your artwork.