A pen holder is a small container or device that is used to hold pens, pencils, or other writing instruments. It can be made of a variety of materials, such as plastic, metal, wood, or leather. Pen holders can come in a range of sizes and shapes, and can be designed to hold a single pen or a collection of pens. They are often used to keep writing instruments organized and easily accessible on a desk or in a bag or briefcase. Some pen holders may also have additional features, such as a built-in clock or a compartment for holding other small items.