Triangular design, twin-tipped pencils doubles the colors. 12 pencils = 24 colors. Ergonomically designed with an easy-to-grip triangular shape for the utmost drawing comfort and the perfect grip. Guides fingers to the proper writing grip and promotes more purposeful and controlled drawing.  Sharpens easily in all standard pencil sharpeners (triangular shape has a circular diameter). Standard size has a 2.9mm pigment core won't break easily under pressure.  Jumbo size has 4.7mm pigment core (maximum break resistant), perfect for young students learning to color!