Gymnic Training Bowls, Adjustable Weight with Water/Sand, 2 Count Incorporating training bowls into your workout can target particular muscle groups to help build power and condition the elasticity of the tendons/muscles Multi-functional piece of equipment that can be used for both fitness activities as well as physical therapy Improve upper/lower/core power, muscle resistance, wrist/ankle strength and joint integrity Phthalate and BPA free; Made from durable, latex-free, vinyl these training bowls are 10 cm each Increase or decrease the weight by filling with water (maximum weight obtainable 3.5 kg) or sand (maximum weight obtainable 5.5 kg)