The ball

Or it’s a way that some people use, and it’s a common term in the lost area. It is a cloth, and it is a circle that is complicated around it so that it does not open, its outer diameter is about 20 centimeters and its inner diameter is 10cm. They don’t do this, and they will increase the level of their knee’s reliance, and it becomes soft, the left arm will be placed on it, and they find the right attachment to their hands, and the arms do not disturb the bone of the knee.