I believe it's important to have simple and easy-to-use items for exercise, and I really like this product. I bought several, so I'm offering them to anyone who wants them. Rectangle, approximately 17x30 cm. When you find something that suits you for sports, you can perform at your best and enjoy it more. Please give it a try. I do boxing, Pilates, and pole dancing. It was easy to use for all of them.