Shapes There are a variety of shapes to choose from including the basic straight barbell, curved barbells, circular barbells, spiral barbells and J curved or banana barbells. Certain shapes are more suitable for particular body areas than others. For example, the straight barbell is usually seen in ear and tongue piercings, the circular barbell is seen in nasal septum piercing and the J curved barbell is the most popular choice for navel piercings.