Canon 24-70mm f4L IS for $800

The Canon 24-70mm f4L IS is on sale for a limited time for $800 at B&H Photo and Adorama and Amazon itself. At the first two, you also get 4% promotional rewards ($32~). Alternately, if you prefer accessories instead of promotional rewards, Adorama has a bundle with various lens-y accessories along with the Corel Creativity software bundle (including AfterShot Pro 2 and Paintshop Pro X7).

In addition to that, Adorama has another listing with the same price but 10% promotional rewards (=$80~). There is an “RB” in the product code and “RW” in the item description, so I’m not sure what this means. I am not sure if RB is short for refurbished? I don’t know what “RW” is.