Here is a link to (one of the) local stores that have "Mexican" groceries.The description calls it Beef Sirloin Tip. This one is sliced, it seems to be the preferred style: Milanese de Pulpa Bola.https://www.heb.com/product-detail/usda-select-mil...I did read somewhere else that "pulpa" means without bone. Strange, as I learned it meant "pulp." Maybe it's a Mexican-Spanish word. There are also pulpa blanca, pulpa negro. Blanca is the top of the flank, I'm assuming white for the "silver skin" that's on it. Negro is the underside of the flank.I added an image from carnesviba.com. Hope this helps.