found at Wild Earth
Like a massage with two fists. Hallelujah! The DUOBALL 12 is the perfect complement for the BLACKROLL. The DUOBALL 12 is particularly good for massaging parallel lines of muscles, for example next to the thoracic and lumbar vertebrae. It can also be used to target the upper thighs and sides. The DUOBALL is available in two different sizes, 8 cm and 12 cm. The two products are perfect when used together. For example, you can use the 8 cm ball for point massage and the 12 cm DUOBALL for larger areas.