What are these color bars?

Many users found it inconvenient that they had to click on a product to see whether or not it was in stock. These color bars denote how many units are in stock of that product.

A product is out of stock
A product has 5 or fewer units in stock
A Product has more than 10 units in stock

If you move the mouse over one of the images, you can see exactly how many units we have in stock.