Shrimp sizes are indicated by numbers-to-pound. For example, 41/50 means that there are between 41 and 50 shrimp per pound. The lower the number, the larger the shrimp. If you see ‘U’ in the size, this means that there are ‘under’ that many per pound. For example, U/10 means there are fewer than 10 shrimp per pound. These are very large shrimp.