S = 10-Pack (Basic Colors with Clip) M = 18-Pack (Basic Colors with Clip) L = 10-Pack (Vibrant Colors) Xl = 10-Pack (Retro Colors). 0.5mm Gel Pens: Featuring classic black barrels paired with vividly colored inks, these pens are the ideal choice for everyday writing. The smooth rollerball tip design effectively prevents ink skipping, while the quick-drying ink formula ensures a fluid, smooth writing experience that resists smudging. Each pen is equipped with a metal clip, allowing it to be easily attached to a notebook or pocket. Whether for office use, signing documents, or serving as a study tool for adults and students, these pens are an excellent choice. Weight: 0.374 lbs.