Bold steel spring, strong and durable, thick foam, soft and comfortable, give you comfortable experience, easy to slim down. Compact design,shaped curve, easy to carry, easy to use,let you at any time slimmingshape. Great for toning thigh muscles while sitting at your desk at work , or even watching TV on the couch. Easy to use. Reduce stress and improve joint flexibility and mobility. It's perfect for home-based strength training.