They are medium sized frozen shrimp shell on. Sorry about not being more specific..
Throw the shrimp whole and unpeeled into a big pot of boiling water with a teaspoon each of dried dill, Old Bay Seasoning, and a pinch of your favorite hot dried pepper flakes. Boil for two or three minutes until the shrimp turn pink and begin to float to the top of the water at which point, immediately remove them from the water and plunge them into a bowl of crushed ice, chill thoroughly and serve with cocktail sauce.