Material: Base Material: Polypropylene, Ball Material: Synthetic Resin, Product Size: Base Diameter 6.5 cm, Height 6.1 cm, Ball Diameter 5.4 cm Resin massage ball consists of a base and a ball. By holding the base, the ball can roll 360 degrees. It is an excellent tool for modern people or athletes who sit for a long time with a hunched back, play 3C with their head down, and have reduced thoracic spine mobility! It is mainly used to massage the neck, thoracic spine, and erector spinae (muscles on both sides of the spine). It can also be used to roll the plantar fascia, calf, thigh, neck, etc. Apply pressure where it's uncomfortable! There is a round hole at the bottom of the base, which can be used to drip essential oils together to promote the absorption of essential oils, killing two birds with one stone! Resin ball design, 360-degree rotating massage Multifunctional, suitable for various parts of the thigh, calf, chest, arms, and neck