What's better than a filet? Filets at half the price. The shape of a tenderloin makes for some uneven steaks when you get to the ends. "Tails" is what the butcher calls them. After they're done making some nice pretty steaks out of the center of the tenderloin, they package up these "tips and tails"
You can generally cook these how you would cook a typical filet. They are really good in breakfast scrambles, chopped up. We also like to use them as kabob meat.
The entire muscle from which the Filet are cut is known as the Tenderloin - which is cut from the lower back of the beef. This muscle has it easy, making for fine muscle fibers and a soft, tender cut. The entire muscle is known as the Tenderloin, whereas steaks cut from the same area are served as Filet Mignon.