Dollar Pens - These pens are Esterbrooks first real entry into the fountain pen market with USA made pens. They are made of hard rubber as well as plastics. These pens featured the interchangeable nibs that were uses in all later models. They are generally well made with the exception of the plain colored models. The plain pattern less plastic is inferior and it shrinks and develops splits. These pens should not be soaked when they are cleaned.