[Trimmed Tip Steak, Ball Tip Steak, Kabob Meat]
This is a roast cut from the Knuckle, the front side of the back leg. It is more tender than other parts of the round, but slow cooking is still recommended. Some stores I know also cut the knuckle into Sirloin Tip Steaks. These are made quite thin to compensate for toughness. One store cuts them about 1/8 inch thick, which makes them difficult to fry without them getting overcooked and dry. The other cuts them even a little thinner, but lays them out so each steak is made up of two slices which are fried together. This is a better plan, keeping the meat moister but still thin enough to eat.
The photo specimen, a sirloin tip roast, was 9-1/2 inches by 6-1/2 inches and 1-1/2 inch thick and weighed 2 pounds 10 ounces, purchased at 2014 US $2.99 / pound (on sale).
More on Cuts of Beef.