The large 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 with the 7cm (small) spikey massage ball to work through trigger points or for dual muscle massage. You can use them with one in each hand, under each foot, placed either side of the spine, or under the buttocks. The larger size provides less intense pressure so if you are looking for a harder pressure we also have a smaller version available in a 7cm size.