This is a bangle with ninja and shuriken set on a Japanese background so that they spin. It totally works, I've tested it myself. The interior diameter of this bangle is about 8cm, but if you have smaller hands than that I have a snugger version here.
This bracelet originated as a metal cuff that I made from sheet copper with a patina for the color. Personally I like the bangle version better, and recommend it in black dyed plastic or if you want to be creative in regular strong and flexible plastic that you can paint yourself and get some variation in the city background and ninjas.