The Sirloin is the hip region of the animal. Tri-tip is quite literally the bottom tip of the Sirloin group. These are between 3-3.5 lbs. Great for grilling, braising, smoking. Or slice it thin and stir fry it up! Cut it in big chunks for kabobs! PRO TIP: Before you cut into this beautiful cut, observe the direction of the grain in the muscle fibers, and cut perpendicular to the grain, not with it.