The adidas 55cm gym ball provides added stability thanks to a dual texture grip and has been made from an anti burst material to guarantee safety while working out this durable swiss ball has a diameter of 55cm 217 which makes it perfect for users between 155cm 167cm 5 1 5 6 tall it is designed to help you improve your balance flexibility and core strength as well as to strengthen abdominal and lower back muscles use the exercise ball for stretching low impact aerobic exer