Set Of Chinese Hand Exercise Balls Blue With Dragon And Pheonix In Blue Box

This is a pair of Chinese hand exercise balls. This pair comes with a box and instructions.
each ball is 1 3/4" (4.5cm) in diameter. The box measures 5 1/4" by 2 1/4" by 2 3/4" (13.5 x 6 x 7cm) They remain in fine condition. A decorative and functional piece of mid 20th century Japan.