Equus

Indicates whether a product is currently available for purchase or delivery. Typical values include "In Stock", "Out of Stock", "Pre‑Order", "Back Order" and similar status indicators that inform customers about the product’s availability at the time of inquiry.

A unique identifier assigned to books and other printed publications, typically consisting of 10 or 13 digits. It may include hyphens for readability but is treated as a string value. The ISBN uniquely identifies a specific edition of a title across the publishing industry.

The calendar date on which the product was first made available to the public or released for sale. It is expressed as a full year, month, and day (YYYY-MM-DD) and can be used to filter or sort items by release period.