Set with Case, Blue Yin Yang Pattern, Sounding Balls, Exercise Balls, Set of 2, Massage These are traditional Chinese exercise balls (Baoding balls). 【Product Description】 This is a set of two exercise balls with a blue color and a Yin Yang mark. When you roll them in your palm, the chimes inside will ring, which is perfect for when you want to relax or exercise your hands. The size is approximately 41mm in diameter, which I think is a common size (measured by an amateur). The material is either wood or resin, I'm not sure, but there are balls inside that make a sound when rolled. 【Condition】 There are no noticeable stains, and I think they are relatively clean. 【Accessories】 Comes with the cloth-covered case shown in the photo. Please check the photos for anything you are concerned about. Thank you for your understanding of used items.