The aeropress is a fun piece of coffee gear to use. Its simple design consists of three plastic parts, a cap, a cylindrical chamber, and a plunger. The basic premise of the aeropress is that you place a single small, round paper filter inside the cap, screw the cap onto the chamber, add coffee and water, wait a short time for brewing, and finally press the resulting liquid through the chamber and past the filter with the plunger.