Maker's Mark 101 is none other than the distillery's famous Kentucky straight bourbon, whose particularity is that it is 101 proof (50.5°).
The story goes that Bill Samuels, founder of Maker's Mark distillery, was the first to appreciate this high-alcohol bourbon. He even served 101 proof to his friends on special occasions.
This bourbon is only produced in small quantities and for short periods during the year.