It sounds like you're describing a stationery box or kit that includes various items. Here's a breakdown of each item you mentioned:

1. Pen: A writing instrument used to apply ink to a surface, typically paper. Pens come in various types, including ballpoint, gel, rollerball, fountain, and more.

2. Book: A bound collection of pages with information, usually made of paper and often used for writing or drawing. Books can come in different forms, such as notebooks, journals, or sketchbooks.

3. Eraser: A tool used for removing pencil marks from paper or other surfaces. Erasers are typically made of rubber or a similar material.

4. Diary: A book for recording personal experiences, thoughts, and reflections. It often serves as a daily record of events and can include a person's feelings and emotions.

5. Sticker: An adhesive-backed decorative or informative item that can be attached to various surfaces. Stickers come in a variety of shapes, sizes, and designs and are often used for decoration or labeling.