Rolex is known for creating some of the best watches on Earth - they are classy, reliable, and incredibly consistent with how well they are built.
It must've taken dozens of years of craftsmanship for the Rolex company to have such a standard quality of their watches. It is because of their high standard for quality that Rolex started selling bags of sand.
What? Sand? Why? Well, think of hour glasses. Hour glasses are filled with sand, but in order to accurately keep track of time - hourglasses have to be specifically built.
Not only do the hourglasses have to be perfect - but the grains of sand all have to be of equal size so they move through the hour glass the same way.
Therefore Rolex took their high standards and consistency and decided to get into the sand making business.
At first it started as an art project, but it later developed into a business. In the picture attached to this article, you'll see a bunch of bags that represent 30 days. That picture represents the average human life span.