The poi is a ball in the end of a string. If the person who is performing the poi is experienced, their manipulating, hitting and twirling of it can make it look easy.

Long Poi
The long poi are done either singularly, doubly or in quad.

Short Poi
The short poi are either done singularly or doubly. It is the short poi that are known for the rythms and sounds, while the long poi usually have bigger movements.