Colors are washable from most surfaces. Easy to store and hard to misplace. Keeps sketch pens from rolling off the desk. Special skin and grey colors. Contains free super connectors which helps in giving angles to the models. Medium point tip for good ink-flow. Click seal cap prevents drying. Broad barrel-big and easy to hold. Simply draw and color or clip these pens together to construct interesting models Contains 40% more ink and lasts longer Child safe-food-grade ink