These are exceptionally large farm-raised Black Tiger Shrimp (Penaeus monodon) sold fresh by the pound at the Costco seafood counter. The "U-18" designation means under 18 shrimp per pound, placing them in the jumbo-to-colossal size range — among the largest shrimp available at retail. Black Tiger Shrimp are recognized by their distinctive dark stripes over a grey-green shell, and are prized for their firm texture and rich, slightly sweet flavor.

Farm-raised primarily in Southeast Asia, these shrimp are previously frozen and thawed for fresh sale at the warehouse. They are well-suited to grilling, steaming, boiling, sautéing, and stir-frying. Their large size makes them ideal for centerpiece presentations such as shrimp cocktails, grilled skewers, and pasta dishes. As with all previously frozen seafood, they should be used within one to two days of purchase and not refrozen once thawed.