A rubber duck is a toy shaped like a stylised duck, and is generally yellow with a flat base. It may be made of rubber or rubber-like material such as vinyl plastic (which is more often used). The yellow rubber duck has achieved an iconic status in American pop culture and is often symbolically linked to bathing. The rubber duck can be referred to informally as a "rubber duckie" or a "rubber ducky". The earliest rubber ducks, produced in the late 19th century, were made from harder rubber.