What are the different haircut machine numbers used by barbers and stylists to achieve various hair lengths and styles?

Barbers and stylists use different haircut machine numbers, also known as guard sizes, to achieve various hair lengths and styles. These numbers typically range from 0.5 to 8, with lower numbers resulting in shorter haircuts and higher numbers resulting in longer haircuts. Each number represents a specific length of hair that will be left on the head after cutting.