This reflex ball is used for hand therapy, relaxation exercises or massage for neck, upper or lower back, hamstring or foot. It's spiky yet gentle texture is designed to relieve tension and helps to promote and stimulate circulation throughout the body.
With 4 different sizes to choose from, each size can be used depending on the surface area of the body (i.e. the 10cm can be used on the back since its much larger and can cover more surface area, whereas the 6cm can be used on the neck since it's a much smaller area compared to the back). But they can also be used interchangeably.