A Whirlwind is another name for a Het For Super Stripe. The first person to produce a Super Stripe was Jared Horenstein and he named the Het For Super Stripes - Specters. Out of respect to the original producer most breeders now refer to them as Specters but Anthony McCain who became involved in the project later has tried to change the name to Whirlwinds. This person trying to sell a possible Specter is capitalizing on the new made up name.
If you would like to see what a guaranteed Het for Super Stripe or Specter looks like you can see one here on BP.net at the following link. This is one I purchased recently that was produced by Mark Haas and is a perfect example for you to compare the one in the ad to. You will have to scroll down on the first page to see all of the pictures but they include a very nice belly shot for you to compare to.