The American Staffordshire Terrier, also known as the AmStaff, is a medium-sized, short-coated American dog breed.The height of an American Staffordshire Terrier is 17-19 inches tall and weighs 40-70 pounds. His head should be medium in length with a broad skull, a distinct stop, and pronounced muscles in the cheek. The ears should be set high on their head and can be cropped or uncropped, but the latter is preferred. Height and weight should be in proportion. The ears should be set high on their head and can be cropped or uncropped, but the latter is preferred. Height and weight should be in proportion.