Ballpoint stick pens feature ergonomic triangular barrels for effortless, fatigue-free writing. Automatic pressure equalization prevents pen leakage while on airplanes. Indelible ink conforms to ISO 12757-2. Transparent barrels show ink color and supply. Cap is equipped with a handy clip to attach to notebooks, pockets and more. Cap color matches brilliant ink color. Assorted set includes pens that write in orange, red, pink, purple, blue, aqua, light green, green, brown and black.