A wall calendar is a calendar intended for placement on a wall. Wall calendars can serve as reminders of holidays, important events, and company events. They typically consist of a collection of images (one per month) on a given subject. Example subjects include automobiles, wildlife, male or female models, etc. Sizes of wall calendars vary, with 12 inches by 12 inches (305 mm by 305 mm)(closed) being a typical size within the United States. Businesses frequently give wall calendars away for free to customers as promotional merchandise.