These ninja shurikens fly quite well especially when printed at high densities and as they are small they don't take long to print even at 100% density. These shurikens would be a great addition to any ninja costume.
The file below needs to be printed twice as it is only one half but it doesn't need supports. the flat side of each half then needs to be glued together
UPDATE: A weighted shuriken is now available which has room for a penny to be put in the center before the two halves are glued together. This gives it more weight and will help it fly better.
NB: Shurikens are prohibited in some places so please check local regulations. The edges of this product are sharp, do not throw around people or animals.