This small spikey massage ball can be used to release tight, uncomfortable muscles and can help to release toxins and improve circulation. Best used as a pair (sold separately) to work through trigger points or for dual muscle massage. You can use them with one in each hand, under each foot or to provide balance when placed either side of the spine, or under the buttocks. The smaller size provides a more intense pressure, if you are looking for a lighter pressure we also have a larger version available in a 9cm size. Features: Material: Phthalate Free PVC Colour: Purple SPECIFICATION: Brand Fitness Mad Usage Home Use, Commercial Use Condition Brand New Warranty 12 Month Warranty